"There was an error importing this build." after Testflight upload

After including bitcode in our app, we have this error popping up after the "processing" state on the Testflight web.


We have followed the instructions here: https://developer.apple.com/library/archive/technotes/tn2432/_index.html

to try and reproduce any issues locally, but archiving and exporting an adhoc build issues 0 complains, the archive+export finishes fine, so we're a bit lost. I've seen some posts where this falls on the apple side, but usually the issues are solved in a couple days. We have this issue since last thursday or so.