Based on the recent comments from users saying that they are no longer encountering this issue after the release of 14.0.1, we are marking this as Fixed.
Adobe InDesign team
An error occurred while saving the commentDavid commented
Same problem here! Also experiencing it sporadically. In my case, it seems to happen in specific pop-up dialog boxes as opposed to options in fixed option menus. Example : I can change the font size via the tool bar in the header - but can not change the page Numbergin styles in the Numbering and Section options... Issue comes and goes, please help us fix it!