can't downgrade apps

• Device OS and version: Android 11
• Device model/manufacturer: Samsung S10e
• F-Droid version (in the About screen): 1.13.1
• F-Droid privileged extension version (if installed):

What did you do? (clear steps if possible)

Select an installed app. Open versions Expand the previous version Press Downgrade & Install

What did you expect to see?

Install the requested version

What did you see instead?

"Failed to install due to an unknown error"

Generally the F-Droid app does not behave well. eg. if I install a new app, it installs and is available to run but F-Droid is unaware that it is installed. It does not appear in the "Manage installed apps" list, and if you visit the app page it still prompts to install the same version. Only after killing the F-Droid app and restarting it does it become aware of the newly installed app. The same applies to app updates.