Most likely comes from 3rd extension.
Please try to disable 3rd plugins for Finder, one by one, to find wich plugin cause the error.

yes I did an it comes from this plugin that cuasing this when enabled: Plugins: Smart Search - Content

I do not have this error with Plugins: Smart Search - Content.
maybe broken upgrade or still some 3rd extension doing some override.

Try enable Debug, and then copy full stacktrace of the error.

Any news about this?

Closing for now. This can be reopened if additional info is provided to reproduce the issue. Thanks.

This is still an issue...

`A PHP Exception occurred on your site. Here you can find the stack trace:
Exception Type: TypeError
File: /var/www/www.site.com/plugins/finder/content/src/Extension/Content.php
Line: 175
Message: Joomla\Plugin\Finder\Content\Extension\Content::onFinderAfterSave(): Argument #1 ($event) must be of type Joomla\CMS\Event\Finder\AfterSaveEvent, Joomla\Event\Event given, called in /var/www/www.site.com/libraries/vendor/joomla/event/src/Dispatcher.php on line 454
#0 /var/www/www.site.com/libraries/vendor/joomla/event/src/Dispatcher.php(454): Joomla\Plugin\Finder\Content\Extension\Content->onFinderAfterSave()
#1 /var/www/www.site.com/administrator/components/com_easysocial/includes/compatibility.php(783): Joomla\Event\Dispatcher->dispatch()
#2 /var/www/www.site.com/administrator/components/com_easysocial/includes/cluster/cluster.php(2618): ESDispatcher::trigger()
#3 /var/www/www.site.com/administrator/components/com_easysocial/includes/group/group.php(1744): SocialCluster->save()
#4 /var/www/www.site.com/administrator/components/com_easysocial/models/groups.php(2270): SocialGroup->save()
#5 /var/www/www.site.com/components/com_easysocial/controllers/groups.php(295): EasySocialModelGroups->createGroup()
#6 /var/www/www.site.com/libraries/src/MVC/Controller/BaseController.php(730): EasySocialControllerGroups->store()
#7 /var/www/www.site.com/components/com_easysocial/controllers/controller.php(67): Joomla\CMS\MVC\Controller\BaseController->execute()
#8 /var/www/www.site.com/components/com_easysocial/easysocial.php(100): EasySocialController->execute()
#9 /var/www/www.site.com/libraries/src/Dispatcher/LegacyComponentDispatcher.php(71): require_once('...')
#10 /var/www/www.site.com/libraries/src/Dispatcher/LegacyComponentDispatcher.php(73): Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher{closure}()
#11 /var/www/www.site.com/libraries/src/Component/ComponentHelper.php(361): Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch()
#12 /var/www/www.site.com/libraries/src/Application/SiteApplication.php(218): Joomla\CMS\Component\ComponentHelper::renderComponent()
#13 /var/www/www.site.com/libraries/src/Application/SiteApplication.php(261): Joomla\CMS\Application\SiteApplication->dispatch()
#14 /var/www/www.site.com/libraries/src/Application/CMSApplication.php(306): Joomla\CMS\Application\SiteApplication->doExecute()
#15 /var/www/www.site.com/includes/app.php(58): Joomla\CMS\Application\CMSApplication->execute()
#16 /var/www/www.site.com/index.php(32): require_once('...')
#17 {main}
Request information
GET variables
Array
(
)
POST variables
Array
(
[cid] => Array
(
[0] => 21
[1] => 22
[2] => 23
[3] => 24
[4] => 25
[5] => 27
[6] => 28
[7] => 29
[8] => 30
[9] => 31
[10] => 32
[11] => 33
[12] => 301
[13] => 302
[14] => 303
[15] => 305
[16] => 307
[17] => 348
)

[es-fields-22] => fsafdfafds
[es-fields-23] => fsafdfafds
[es-fields-24] => <p>sdfafdsa</p>

 

dfafdaf

[group_type] => 1 [photo_albums] => 1 [videos] => 1 [es-fields-29] => 1 [es-fields-30] => 1 [es-fields-32] => Array ( [source] => [path] => [data] => {"top":null,"left":null,"width":null,"height":null} [type] => [name] => )

[es-fields-33] => Array
    (
        [data] => 
        [position] => 
    )

[group_notification] => 1
[audios] => 1
[events] => 1
[es-fields-305] => 1
[es-fields-307] => 1
[conditionalRequired] => 
[currentStep] => 1
[task] => store
[boxchecked] => 0
[option] => com_easysocial
[controller] => groups
[6971a840af41cb316e9de77d732cb821] => 1

)

COOKIE variables

Array
(
[linkedin_rescue_state] => afc132a6c4a9ced4b1f038e58db46787
[81dbc6c0e8060ce065ce1f9025ed2ea1] => odhchuege2v13ehq5ei8ear4f7
[a5e4d6bfa5193f2e9c9d384efe68c1ad] => 4f0g359flmbqt8ccqb75ie44ui
[_ga_DPYRW84SWK] => GS1.1.1730044634.1.1.1730044678.0.0.0
[_ga] => GA1.1.1561123787.1730044634
[visitortime] => 1730044664912
[cookieconsent_status] => dismiss
[joomla_user_state] => logged_in
)

REQUEST variables

Array
(
[cid] => Array
(
[0] => 21
[1] => 22
[2] => 23
[3] => 24
[4] => 25
[5] => 27
[6] => 28
[7] => 29
[8] => 30
[9] => 31
[10] => 32
[11] => 33
[12] => 301
[13] => 302
[14] => 303
[15] => 305
[16] => 307
[17] => 348
)

[es-fields-22] => fsafdfafds
[es-fields-23] => fsafdfafds
[es-fields-24] => <p>sdfafdsa</p>

 

dfafdaf

[group_type] => 1 [photo_albums] => 1 [videos] => 1 [es-fields-29] => 1 [es-fields-30] => 1 [es-fields-32] => Array ( [source] => [path] => [data] => {"top":null,"left":null,"width":null,"height":null} [type] => [name] => )

[es-fields-33] => Array
    (
        [data] => 
        [position] => 
    )

[group_notification] => 1
[audios] => 1
[events] => 1
[es-fields-305] => 1
[es-fields-307] => 1
[conditionalRequired] => 
[currentStep] => 1
[task] => store
[boxchecked] => 0
[option] => com_easysocial
[controller] => groups
[6971a840af41cb316e9de77d732cb821] => 1

)
SERVER variables
Array
(
[REDIRECT_HTTP_AUTHORIZATION] =>
[REDIRECT_HTTPS] => on
[REDIRECT_SSL_TLS_SNI] => www.site.com
[REDIRECT_STATUS] => 200
[HTTP_AUTHORIZATION] =>
[HTTPS] => on
[SSL_TLS_SNI] => www.site.com
[HTTP_HOST] => www.site.com
[HTTP_USER_AGENT] => Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:131.0) Gecko/20100101 Firefox/131.0
[HTTP_ACCEPT] => text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,/;q=0.8
[HTTP_ACCEPT_LANGUAGE] => sv-SE
[HTTP_ACCEPT_ENCODING] => gzip, deflate, br, zstd
[HTTP_REFERER] => https://www.site.com//en/what-to-do-grupper/step/1/
[CONTENT_TYPE] => multipart/form-data; boundary=---------------------------22782878322051455441201297079
[CONTENT_LENGTH] => 6722
[HTTP_ORIGIN] => https://www.site.com
[HTTP_DNT] => 1
[HTTP_SEC_GPC] => 1
[HTTP_CONNECTION] => keep-alive
[HTTP_COOKIE] => linkedin_rescue_state=afc132a6c4a9ced4b1f038e58db46787; 81dbc6c0e8060ce065ce1f9025ed2ea1=odhchuege2v13ehq5ei8ear4f7; a5e4d6bfa5193f2e9c9d384efe68c1ad=4f0g359flmbqt8ccqb75ie44ui; _ga_DPYRW84SWK=GS1.1.1730044634.1.1.1730044678.0.0.0; _ga=GA1.1.1561123787.1730044634; visitortime=1730044664912; cookieconsent_status=dismiss; joomla_user_state=logged_in
[HTTP_UPGRADE_INSECURE_REQUESTS] => 1
[HTTP_SEC_FETCH_DEST] => document
[HTTP_SEC_FETCH_MODE] => navigate
[HTTP_SEC_FETCH_SITE] => same-origin
[HTTP_SEC_FETCH_USER] => ?1
[HTTP_PRIORITY] => u=0, i
[PATH] => /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
[SERVER_SIGNATURE] =>
[SERVER_SOFTWARE] => Apache/2.4.52 (Ubuntu)
[SERVER_NAME] => www.site.com
[SERVER_ADDR] => xxx.xxx.xxx.xx
[SERVER_PORT] => 443
[REMOTE_ADDR] => xxx.xxx.xxx.xx
[DOCUMENT_ROOT] => /var/www/www.site.com
[REQUEST_SCHEME] => https
[CONTEXT_PREFIX] =>
[CONTEXT_DOCUMENT_ROOT] => /var/www/www.site.com
[SERVER_ADMIN] => webmaster@site.com
[SCRIPT_FILENAME] => /var/www/www.site.com/index.php
[REMOTE_PORT] => 60909
[REDIRECT_URL] => /en/what-to-do-grupper/step/1/
[GATEWAY_INTERFACE] => CGI/1.1
[SERVER_PROTOCOL] => HTTP/1.1
[REQUEST_METHOD] => POST
[QUERY_STRING] =>
[REQUEST_URI] => /en/what-to-do-grupper/step/1/
[SCRIPT_NAME] => /index.php
[PHP_SELF] => /index.php
[REQUEST_TIME_FLOAT] => 1730044680.621
[REQUEST_TIME] => 1730044680
)
`

I disagree that this is a Joomla bug. This is triggered by a third party extension and that third party extension on their homepage is only claiming Joomla 4 support.

By looking the trace, it the same as #43103
The bug is in EasySocial, see linked comment #43103 (comment)