I've seen this question (about whether standing from prone triggers the Booming Blade additional damage) and this one (whether other actions trigger it), but neither seems to address exactly what I'm wondering.
Does teleportation trigger the additional damage from Booming Blade?
Booming Blade's spell description states:
As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.
There seems to be some debate on the internet over it, but I don't see any official answer to this from Jeremy Crawford or anything. It seems unclear, since it doesn't use the character's own movement, but obviously teleportation does cause them to end up in a different spot.
To me, it seems as if it wouldn't trigger the additional damage, assuming it works similarly to opportunity attacks... But it doesn't necessarily work the same way. I'd appreciate anyone pointing me to an official ruling one way or the other, or at least making a compelling argument why the rules (or logic) suggest that teleportation should or shouldn't trigger the additional damage.