The automatic filewatcher seems to fail when Taiga is started automatically with windows. This doesn't happen always however. Reopening Taiga fixes the problem 100% of the time.
I bypassed the issue by disabling automatic startup in Taiga and adding a task scheduler entry with a 40sec delay.

This issue started after upgrading my PC. Taiga now starts much faster, so maybe there's a timing issue somewhere.

Win10 -> Win11
Ryzen 1600 -> Ryzen 9900X

Edit: Nevermind the problem still happens with a 40sec delay...