OpenAI, stop breaking 4o every week

Every week, OpenAI rolls out an update that pretty much breaks the custom 4o GPTs made in the chatgpt web interface.
Why? Is this an advert for GROK?
Huge number of errors, and almost total disregard for instructions that haven’t changed in almost half a year…

Support also doesn’t work. When attempt to log-in on auth open-ai web interface:

Unexpected token '<', "<!DOCTYPE "... is not valid JSON

upd: Looks like GPT started ignoring jit_plugin usage again like a month ago. Even if this point is stated many times in the instructions.