TinyMCE editor keeps reloading

I am running Windows 10 on a desktop pc. I have Firefox for Windows 148.0. I am editing a website on Joomla 5.4.3. To edit pages in Joomla, I use the TinyMCE editor. Since today, whenever I open a page in the editor, the editor keeps reloading constantly which renders the editing impossible. After I close the editor, the browser seems to lag for 5 to 10 seconds, before returning back to its normal, problem-free behaviour. This behaviour is only happening in the Firefox browser, not in others on the desktop. I switched to my Macbook, which still had Firefox for iOS 147.0.4 running. There the above mentioned behaviour didn't occur. But when I updated Firefox for iOS to 148.0 the behaviour did start to occur. So, I guess it is a bug in version 148.0? How can this problem be fixed?