wrong login page after activating 2FA with non-root installations

[unDocUMeantIt]

i have accounts on three seafile servers (all 9.0.*) and had previously succesfully used the link in the desktop client (currently 8.0.5) for login. after i had activated 2FA on all three accounts, using the link failed to work in an unexpected way for two of the three servers.

on the one still working (i.e., i now get to the login page), seafile is is running on the root of the domain. the two failing servers have seafile running in a non-root location: using the link in the desktop client now directs me to an URL in the browser where the non-root part of the address is used twice (i.e., if https://myserver.com/seafile/ was correct, i now end up with https://myserver.com/seafile/seafile/). this still does not happen to other users on those servers that don't use 2FA. also, right-clicking on the link and copy-pasting it directly to a browser also still get's me to the correct login page.

i've had this issue since i activated 2FA back on seafile server CE version 8.* and with all desktop clients since then (multiple installations on various PCs). a post in the support forum didn't get any reply since april 2022.