Thank you for your report. This is actually a defect in the recent WordPress 5.4.2 update, not in MLA itself.
WordPress 5.4.2 changed the way these option settings are processed and the new process is not compatible with any existing software that uses the “old process”.
In MLA this affects the Media/Assistant admin submenu as well as several of the tabs in the Settings/Media Library Assistant submenu page.
I have uploaded a new MLA Development Version dated 20200707 that contains a fix for this issue. To get the Development Version you can follow the instructions in this earlier topic:
PHP Warning on media upload with Polylang
It would be great if you can install the Development Version and let me know how it works for you. I plan to update the MLA production version within a week or so.
If you cannot try the Development Version you can set the items per page with this workaround:
- Navigate to the Settings/Media Library Assistant General tab.
- Scroll down to the “Table Defaults” section.
- Change the “Entries per page” setting to the value you want.
- Scroll to the bottom of the page and click “Save Changes” to record your new setting.
Either the Development Version or the workaround should get you past the problem.
I will leave this topic unresolved for now. Please let me know if you try the Development Version. Thanks for your help and for your interest in the plugin.