Recently i tested in sandbox mode various tactics and found strange result with nova towers: i placed lvl 3 nova in the middle of upper left location and lvl 2 nova in the middle of upper right location. So they have some shared aoe(approximately 250). When creeps walks further with 70% slow from sharing aoe of both nova towers, then they unexpectedly don't change slow effect to 30% and moving forever with 70% slow untill death.
I also tested this effect in game(All Pick Normal) without sandbox
- match 2612147677
result was same and definitely this bug gives huge advantage.