Hi @klaczko -- When you say it doesn't save, I assume that things may appear to revert back to their initial places. Am I correct?
After moving an item, does it hop immediately back to the original space, or is it there after you navigate away from the page and use the "back" button to return? Sometimes, if the latter, a good page refresh reveals the changes.
If you have time time to create a short screen recording, that would be really helpful!
If it works in an incognito mode, I wonder if you have a Chrome add-on or extension that is causing a conflict. I was using an ad-blocker that was presenting some files from showing in the speedgrader. Perhaps you have a similar issue. As @klundstrum suggested, I would try downloading FireFox or Microsoft Edge to see if it works in those browsers.
I have a teacher experiencing a similar problem. She organized her module the way she wanted, then the next day some of her assignments moved to a different location within the module. Could this have anything to do with a new sync from blueprint? It has not happened before.