Google Search Console - Strange Crawl Error

On my Google Search Console, I was recently notified that there is a lot of 404 errors:

However, the results are listing pages that never existed in the first place. I’m trying to narrow down why this is the case. Would any of these be Bubble-related?

I’ve seen a few other cases of this happening on the forum. @romanmg was this something you encountered?

Yes, here: Dozens of 404 Errors

While it eventually stopped for me, the cause is still a mystery.