Mocha has a feature allowing to retry a test if it fails (which is almost the standard behaviour for some of our tests).
https://mochajs.org/#retry-tests
Adding that at a configuration level could spare us a lot of false-positives (and therefore, spare us frustration and time too).
From what I could read and try, the possibility exists and the feature is precisely meant for those tests which are (somewhat) randomly failing.
For the webapps, it would require to rewrite a lot of tests because the retries option only re-execute code in "beforeEach/afterEach" statements (and we mostly use the "before/after" ones).