Might be the same as I saw.

I debugged something similar in Angular about 18 months ago, didn't have time to report it and blamed it on Google not testing in other browsers.

Not just Angular. My Vue app as well. I can't figure out why Firefox doesn't just display the error.

I'd love to know more about the setup here. I am aware of https://bugzilla.mozilla.org/show_bug.cgi?id=1595046 which is for cases when someone rejects a Promise with a non-Error (and non-DOMException, I suspect) object. Is that what's going on here? Or could it be the thing described in https://bugzilla.mozilla.org/show_bug.cgi?id=1595046#c5 with throwing a random non-Error object and the resulting console interaction?

I think it might have been the first case you described. I have only recently switched over to Firefox and that was my first debugging experience with it, so I didn't realise it was a specific case and a known bug. Thank you.