To be honest I am getting out of plumes now 95% of the time, by reacting, not by moving preemptively. I guess I just learned to workaround this crappy netcode.
I have simple rules doing this with bard:
1. Never use skill while in plume range
2. Stop asap as I am out of aoe (you can even be touching the plume with one of your feet)
3. Spam abilities asap as I am out of aoe

If you do it like that, it almost feels like it's working fine

I'm not claiming there is no problem, just offering a friendly tip for fellow bards.