See next heading. Actually, it's entirely a Turbo issue where they hard code completely re-evaluating all scripts if the response was non-successful, i.e. a 4xx or 5xx error; see comments in hotwired/turbo#1190
Visit a 404 or 403 or other 4xx page; note console debug messages are logged an additional time after a page or two after the 4xx page, resulting in 2, 3, 4, and so on instances of the same message, and depending on the other JavaScript and how it's handling behaviours, will probably start to result in errors.
This is something that Turbo hard codes (see hotwired/turbo#1190) so we'll have to patch Turbo ourselves in the short term, and contribute a fix in the longer term.
See above.
Stuff no longer borked.
None.
None.
Postponed
2.0
Code
Updated info as we now know what's causing this.
Rewrote proposed resolution with clearer solutions.