Spell cascade & cursed ground bug

Hello, I've encountered a bug using a curse supported with cursed ground and spell cascade support. I'm using the combo to proc impending doom explosion on monsters.

The problem is that once the cast time of my curse is lower than 0.51s (anything 0.51s and up works as intended) the cascade stops creating cursed ground in the middle of the screen and only procs it on the sides. Seems like a bug, any comment from a developer would be appreciated.

Thanks