Randomly: Executed 0 of 0 SUCCESS

[elalish]

We've been using Karma as our test runner for years, and have it integrated with BrowserStack in our Github Actions CI. What we've recently noticed is that we randomly get erroneously passing tests. For instance, go here and open the "Unit tests" section. There's a lot of spew, but if you search "success", you'll see several like this:
Chrome 100.0.4896.127 (Android 11): Executed 0 of 0 SUCCESS (0.002 secs / 0 secs) (incorrect)
and several like this:
Chrome 103.0.5060.114 (Windows 10): Executed 410 of 418 (skipped 8) SUCCESS (52.855 secs / 23.444 secs) (correct)

Now, we can see on the BrowserStack side that Karma has connected to the Android Chrome browser (same thing on several other devices, but not consistently), but it indeed doesn't run any tests. So it appears Karma isn't sending any (0 out of 0), but what would cause this? And why unpredictably?

Obviously it would be great to get pointers fixing this (here is our karma.conf), but I think the bigger bug is that these are returning SUCCESS when the tests all failed to even run. I have no idea how long this has been happening because it doesn't cause our CI to fail. If nothing else perhaps ensure if the total tests == 0, that returns a failure, since that's pretty clearly a case of something going wrong?