When adding layer effect to one symbol, other symbols follows as expected. However pressing merge and it now applies to only that one symbol, a bunch of unlinks appeared, the orange line became dashed, and undoing cannot restore back the linked state.
Related question, how can I intentionally unlink some "attribute" that it is showing here? What are available attributes that I could unlink manually? How to relink them? Any documentation of this "dashed line" symbol?
unlink.mov
unlink.afdesign