I want to second this - I have this problem frequently, but only with Altman fixtures.
Once it happens, no matter how many times I undo/delete & reinsert/replace, etc, the symbol changes everytime I sync with lightwright, or attempt to edit the fixture in every way.
It is NOT associated with a specific label legend, because fixtures of other types using the same label legend are not affected.
Any other ideas how to fix this?
Thanks,
Luke