Release canidate assembly has errors on release page, but not in assembly.

I have run into this issue when attempting to release an assembly, where it throws an error in the release candidate tab.

Usually when I get this specific error, I can resolve some parts or mates with the attached error flag,

Okay, no problem. Let's just find the error.

Nope.🤨

I also manually searched the menu, through all of my configurations, and still found nothing. Assembly contains no faults. Where's the next place to look?