Despite having Self Buff on first it seems to be prioritizing other raid members with single buffs before casting one on yourself. Experienced this in battlegrounds - can't confirm if it's the same in raids and would have to double-check (and there might not be any difference).

Current settings;

Prevent PvP Tag
Pause if someone is Dead
Avoid Group Buffing
Self First
Don't use consumables

Note: it seems to work occasionally, but 9/10 it doesn't.

Update: Mainly occurring in Battlegrounds. Seems to target others before yourself.