How does Rewind Time work?

Anyone else have issues with rewind time?

heals sometimes but not always it seems. Is it somehow connected to how much dmg/healing being received by the target during the time frame? i.e., if they don’t change net % it doesn’t do anything?

Yeah i have the same problem

Yea it requires great timing to be worth taking AB over it. Super fun in PvP, but thats where it belongs. unless arcane healer gets some good abilities to replace arcane blast, youre not taking it regularly

I get that timing is important with it (obviously as they need the buff for 5 secs prior as starters) but it’s unclear to me how it even functions as sometimes if I’m spamming regen on a target for say 3 casts and then hit RT, it may do nothing.
This leads me to think its either bugged or it’s based on net %hp change as opposed to how much just flat dmg they took in the prior 5 seconds as per the tooltip. Both cases should be fixed.
Or maybe certain dmg isnt being calculated, like dots or something?