If the script is breaking a user's ability to login

A personal case: When I was trying to log in on any Wikipedia site where reverse proxy is used personally, it would return "502 Bad Gateway" during the "index.php?title=Special:UserLogin" attempt.

In T383428#10457657, @matthiasmullie wrote:

I am unfortunately unable to reproduce this, or even think of a plausible cause for what's happening here.
The only thing I can think of would be T383637 causing additional cascading JS issues, although even that seems unlikely.

Can you check whether this still happens for you, and if so, check whether there is anything in the browser's console and share those files that present these problems?

Screenshot of the date field problem as of 16:10, 28 March 2019 (UTC): The original photo taken at 17:07:54 (UTC+8), and the retouched photo is modified at 23:09:05 (UTC+8).