Rayne's poison not spreading when I copy with Lord Loki

I’m not sure if Rayne’s poison was getting overwritten by Bera’s. It’s the only thing I can think of that was happening. But they have different icons, so is that working as intended? Everytime Rayne hit me, the poison spread. Everytime I copied her spell with Lord Loki, it didn’t spread. However, the enemies were also under the effect of Bera’s poison. So was Bera’s poison overwriting Rayne’s?

Also, is there a way to attach videos here? I have a short video of it.

Regular poison can overwrite Rayne’s poison, not a bug.