[smokel]

Multiple times have I blamed compilers, cosmic rays, quantum effects, or at the very least an obscure kernel bug, before realizing that I was the source of a bug.

A collision at 15,000 records is so unlikely that I would first suspect something else. Duplicate processing, replayed requests, reused objects, misleading logs, or another code path reusing the identifier.

Could you share a bit more of the surrounding code so we can check?