Public_wopi_url dot escaped

I have a weird problem with Collabora: public_wopi_url gets stored dot-escaped. This makes loading Collabora impossible.
image

I fear I did tweak something in an attempt to figure out #2065, but I cannot find what if something was changed. I tried reinstalling the app but it still misbehaves. I tried deleting the row, updating the row without the backslashes, but every time I save settings the param is restored wrong.

I ran

occ integrity:check-app richdocuments
occ integrity:check-core

and they both return no errors.

I donโ€™t know where else to look at. Suggestions welcome :wink:
Thanks