Sup!
PLAYER_TALENT_UPDATE is what we internally call a unitless event, it just fires and has no args. I just checked and we too use it internally, but for some reason it's not in our
unitlessEvents table, so I'll PR it ASAP.
But in general, when you're writing your own tags that rely on unitless events that aren't known to oUF, you need to add them manually from inside your layout code like so
Lua Code:
oUF.Tags.SharedEvents["PLAYER_TALENT_UPDATE"] = true