Not sure if it's new with this expansion, but this is what happens:
- I have myself as the target all the time.
- I cast Powerword:Shield
- I'm trying to cast it again before the forbearance debuff has expired and it wants me to target someone else.
- Trying to cast Powerword:Shield again now with the forbearance debuff gone but it still doesnt want to cast, so I have to re-target/click myself.
This can get annoying in arena, when you might start spamming just before forbearance is actually gone, also happens with druids swiftmend and probably lots of other spells.