uncaught exception on fetch

[duncdrum]

on 6.4.0 I can locally reproduce the uncaught fetch exceptions that come on during CI runs. They seem to originate in editor.js racing with css resources.

Needs more debugging, no matter the intervention in editor.js the errors keep coming back.

[tuurma]

are these popping up all over the place or in some specific tests only (I vaguely remember one case it happened)? We could sit together on it next week for a bit, but if the problem remains elusive, I'd be partial to rewriting tests a bit.

[duncdrum]

the errors appear in multiple places. They are currently not failing the test runs. As I can reproduce them locally, I don't think that triggering the errors is specific to how the tests are written. But if you can find a way to remove the exception watcher, and not trigger the errors during test runs that would be an improvement. However, I strongly suspect we need to fix editor.js so the errors don't occur in the first place.