This is what overnight "regression" & "aging" (where you run the test suite over and over, to try and capture those rarely-seen corner cases) tests are supposed

This is what overnight "regression" & "aging" (where you run the test suite over and over, to try and capture those rarely-seen corner cases) tests are supposed to capture. I'd be surprised if the VM developers didn't run these. More likely, the environment the VMs are run in has changed in the decades since their development: amount of RAM, cache size, latency of one subsystem over another....