Battle roar gives HP only if it appers on buffs bar (overwrites buffs which increases HP). Example: if you have bless the body 6lvl (+35% HP), battle roar 2lvl (+15% HP) will not overwrite it = will not heal you.
So basically if you have newbie bless the body, battle roar will not heal it until its 6lvl.
Combo from PP/OL cannot be overwrited at all by battle roar (it gives more max. HP + more max MP which is considered as a stronger/better buff).
Get buffs from newbie buffer, remove btb, use battle roar. Tadam, it works now.
Clear enough?