strange Nova slow bug

[Bercut32]

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.

[WindStrike]

Yeah, I ran into that bug a few days ago on accident. It worked w/ a Level 3 & a Level 1, buuut as of the recent Patch 1.12, that bug is fixed.