Solutions
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ph_'s post in Some shared folders only sub-directories accessible from Mac OS, not top directory. was marked as the answerResolved it by first duplicating the 2 affected shares then deleting the old ones and renaming the new ones to the previous names on unraid. That solved the lock sign on the shares in OSX. Then removed and then recreated the crashing nextcloud sync connection.
not elegant... but did the job.