I'm running last version of Lightroom on Mac OS Catalina 10.15.7
I've just realized that there is a bug (I think) never seen before: I used to tag photos both with keywords for metadata export both for my personal internal search use only.
In previous versions it was easy to note that a specific keywords should not be exported, just double clicking the tag on keyword list and dialog box let you choose if that specific keyword should be exported or not.
Now it seems that this do not work anymore.
The dialog box still appears but checking or unchecking any of the choices (not only the include / exclude from export) does not give any results. And now if I export image it contains all keywords, also that ones that I usually exlude.