WordPress bug problem: Update causes override with text

I recently updated my WordPress into the latest version, and ever since I’ve encountered some errors, whenever I update my WordPress site. The error I get is whenever I write something and save/update a page, the text jumps up and overrides with another text. I haven’t had this problem before the new update. I have 2 different WordPress sites and I have tried on them both and on different operative systems and different browers, but I still get the same error (I have even tried to look on the HTLM view to see if anything is wrong or missing, but all I see it that the ”&nbsp” dissappears in the HTLM view on the page) . Is this some kind of a bug and if so, when will there be an update fixing the problem?
Can anyone help me? Please… Thanks in advance!