Thank you for reporting.

Could you describe what you did to get this warning?

#37009 was another piece of code.

I am using the com_jevents component in which the Clean() method is called.
The file path is: components\com_jevents\libraries\gwejson_findcreator.php
Line: 63
The code responsible for the call: $title = InputFilter::getInstance()->clean($requestObject->typeahead, "string");

"My" gwejson_findcreator.php uses library

use Joomla\CMS\Filter\InputFilter;

which is file libraries\src\Filter\InputFilter.php

But in your first post you say it's file libraries\vendor\joomla\filter\src\InputFilter.php (use Joomla\Filter\InputFilter;)

Could you please check which use line is used in "your" gwejson_findcreator.php

use Joomla\CMS\Filter\InputFilter;

The library and the component as a whole uses Joomla\CMS\Filter\InputFilter, but an error on the site leads to the file libraries\vendor\joomla\filter\src\InputFilter.php , which is called as: Joomla\Filter\InputFilter.

I tried changing it to Joomla\Filter\InputFilter, but it didn't give much result.

InputFilter accesses the clean method and there I tried to pass the type (string) to the parameters, which also did not give results.

I'm sorry, but you are saying that you are using Joomla 4.3. Please update to at least Joomla 4.4. We don't support 4.3 anymore. To be honest, if this is an issue on Joomlas side, there is a very big chance that we fixed it in 4.4 already and otherwise you have to contact the developer of the extension to fix this. Please report back when you still encounter this issue on 4.4. If that is the case, we can open this issue again, but for now I'm closing this.

I updated the joomla version to 4.4.3 and my error remained.
We fix it like this on line 213
$type = ucfirst(strtolower($type));
$type = ucfirst(strtolower((string) $type));
like here: #37009