Are you using Linguistic Focus? We’ve recently discovered that when this is invoked, quotes are added straight, but then the immediate conversion to curly does not happen, especially in Compose mode.
You have to then turn off LF, and sometimes you have to add a space after the quote mark, briefly, to get it to change to curly.
Until that is addressed, It might be a good idea to do a ‘straight to curly’ transformation to the entire document once completed.