I encountered it for the first time. All settings are default I haven't played any (new installation).
Joomla 4.1. new installation. I click on the Media link from the menu and I see this warning.
Property 'mime_type' of argument 'item' of event onFetchMediaItems has a wrong item. Valid: string
PHP version: 8.0
No Code Attached Yet
|Closed_Date||0000-00-00 00:00:00||⇒||2022-02-15 15:29:30|
Despite not being at the technical level of the above users I had to find me own fix as none of the above worked for me. I had two J4 sites where I had ticked fileinfo in cPanel PHP Selector but in System Information Fileinfo showed up as no. So my settings were being ignored or overridden. I had success only after I went to my WHM and made server wide changes to my EasyApache4 settings. Then it worked. I have my own webserver not shared.