1.7.3.1 Problem saving products on version 1.7.3.1

[PK777]

Our shop has been having a strange problem for the past couple of months. We are unable to save changes in products on some computers. For example, everything works perfectly fine on my computer but not on my boss's computer, sometimes changes are saved fine right away, sometimes you have to try a few times before it works, sometimes it takes hours of clicking "save" before the change is actually saved, and sometimes only some select fields are saved. It's even worse on other computers where we can't save anything at all. The strangest thing is that I'm using the exact same browser as my boss (Firefox version 85.0.2). We think this might have something to do with cache settings since clearing the cache does solve the problem for a moment (as in, we're able to save changes for a few minutes before everything stops working again). I have seen multiple people report similar issues but none of them mentioned not being able to save changes only on certain computers. The only thing that always works is the product picture, which is always saved, no matter what computer is used. Does anyone have any idea what could've caused this and how to fix it?

Edited February 10, 2021 by PK777 (see edit history)

[PK777]

I forgot to add, we are getting absolutely no errors in the browser console, and the website always displays a "saved" message, even if the data wasn't actually saved.

[PK777]

Anyone?

On a side note, I've managed to replicate the error, sort of; we have a lot of products with no category (might be a part of the problem, I am not entirely sure why and how these products are created) and if I pick one and try to assign a category to it, and then hit save, nothing gets changed. Products are saved if I edit anything except the category, after that the product is assigned to the default category and it is then possible to change it.