Quick update: As expected, the second submission was rejected again as the In-App Purchase is not visible. I'm now waiting for a response for the contact form I submitted.

I have reached out via the contact form you provided and was sent to the "Feedback Assistant" app. I created a feedback there on November 26th including a screen recording of the issue as both a file attachment and a link to an unlisted YouTube video. On December 2nd, I received a response requesting me to attach the video again, which I did on December 4th. Since then, I haven't heard back. The issue I opened runs under FB15965060.

Thank you for the quick response! I've just submitted a bug report with the ID FB16272513.