There are new revisions to the 34xxSP hardware, it seems that the first units have been delivered in the last couple of days.
Most likely a new screen in your case.
MustardOS currently does not support these new screen revisions.
If it ever does, that wouldn’t be before the next major release.
There is a custom/alpha version of knulli that was reported to work, you can search their discord server for that, it seems to be public.