They don't continually stack as much as they used to from one set ...... but they can and do still stack from multiple sets. So 3 sets means 6 yellow buffs each turn... and 6 grey buffs for enemies. That's the issue. Limit everything to 2 maybe 3 buffs of each kind.. problem solved and eliminate the benefit some got from the broken vortex fills.
I have 2 sets... I use 1 on attack, but you can bet I'll use both on defense until this is fixed.
As Stormeye points out.. I can't see how these are at all helpful for new players. Heck it was a month before I could do one vortex fill when I started playing. So teams with 2, 3, 4 sets of these have an unfair advantage because of how broken they are.. apparently NF never dreamed of a situation where any one player had more than one set... idiots.