Comment by Groxx

Yep - I've seen legitimate-looking dups on bad hardware, and "there are a ton of trailing zeros" is also an incredibly common duplicate mode for some UUID libraries (like earlier Go ones that didn't validate the "requested N bytes, returned 3, you must re-request to get N-3 more" return values. it doesn't happen on most hardware or OSes, so people never check it, so it just comes up in production some day with tens of thousands of collisions).