Proxy creation inserted black frame with text in one clip

Something odd happened mid December but we got busy with holidays etc. I'd like to come back to it.

For one of our projects, in our usual workflow we ran proxy creation after importing into Premiere Pro.

The editor assigned to this proj came back saying there is a faulty frame in one of the proxies.

We noticed that the following frame was generated in the proxy file which wasn't present in the OCN.

This is the weirdest bug I've ever seen. We do not have any other leads that could help understand what happened. My best guess is something related to memory/cache behaving unexpectedly. Or some other issue within AME perhaps.

I wonder if this piece of text is present in Adobe's software somewhere in the code or anything?

Hoping the team can look at this. I'm able to share additional files confidentially if needed.

Thanks.