ext: form hangs (run into 500 error) when a lot of files are in the fileadmin
TYPO3 9.5.8 with many many many files in the fileadmin directory.
if you click on the modul form in the backend, the form module loads dead - until it runs into the php_exectuion_time or produces 500 errors - "Premature end of script headers: index.php". (the SQL process that is started is sleeping and will not be aborted)
This only happens if there are 100d of files in the fileadmin. Although the allowed "allowedFileMounts" or "allowedExtensionPaths" are explicitly specified in custom BaseSetup.yaml.
If you move the files from fileadmin to a parent dir / outside of fileadmin - all works fine.