Not seeing any mobs in new instances I just created.  please help

Can you make it so that Timeless Vampiric Thunder 1 gets overwritten by Timeless Vampiric 2 on buffs?  It should technically overwrite it since it is the same spell just a higher level version?

There's too many times my buff slots are full and I don't get VT2 when I already have VT when it's mass buffed