I would say that your non-deterministic components here weren't a good thing - instead the test was poorly written and didn't cover the assumptions of the code under test well. The fact that this bug was revealed by a test is useful, but I should hope that now the tests have cemented that case in a regression suite in a deterministic manner.
> the test was poorly written and didn't cover the assumptions of the code under test well
That's a cop out, you rarely know all the assumptions of all the code. The point of tests is to hopefully suss out those unknowns. Just saying "you should think harder and write better tests" doesn't result in better code.
I don't disagree that it's hard to know all these shortfalls ahead of time, that's sort of why software has bugs and why all us devs stare in amazement anytime it's suggested "Could you folks just... write less bugs" but when the builds start to fail it should be acknowledged that your tests are incomplete, and it should (ideally) be a high priority task to either revert out the feature or fix the feature to resolve the issue. (There are all sorts of reasons this could be difficult, but I'd urge you to advocate strongly for fixing bugs as a higher priority task than feature work - it ends up saving businesses money)
