I had a similarly maddening issue (circa 2014) once where small chunks of memory would randomly get overwritten on PV-virtualized AWS instances, but not on HVM-

I had a similarly maddening issue (circa 2014) once where small chunks of memory would randomly get overwritten on PV-virtualized AWS instances, but not on HVM-virtualized instances. We spent an enormous amount of time chasing this problem; the most senior engineer on the team wrote a test case that would have to write 100TB of data before reliably reproducing the issue. We never did figure out what caused it. Eventually we migrated all our instances to be HVM-only, and the problem went away.