Firefox and Safari Xerte editing problems

Since the update to v3.9.1, I have been experiencing problems editing Projects in Firefox and in Safari. The problems are: (i) opening, closing and then opening the same project again leads to a blank screen or very slow opening; (ii) warnings that projects that I have already closed are locked for editing by me; and (iii) unable or very slow logout. These issues do not occur instantly or every time, but after a while of editing Projects they always reoccur. It's all the same even after restarting, deleting cache / cookies or using a private browsing window. Is this a known issue?

Chrome seems fine for me, which makes me think the issue may not be with Xerte potentially not being optimized for M1 MacBooks.

I'll have a look. The only thing I do know is that issue (ii) is probably caused by issue (i).

How many LO's do you have in your workspace?

I have 85 LOs in my workspace.

These problems were not occurring before the update, when I had the same number of LOs in my workspace.

Edit 08.01: The same problems as above are now happening in Chrome too.