Problem : Corruption doesn't update correctly when casted over itself with procs, however it updates correctly with fel flame, or by casting it without corruption up. UA and agony are completely unaffected by this and will update normally just by recasting.
Has anyone else actually noticed this or understand why it happens. It is very easy to reproduce so I will explain the steps to better understand the problem. I will also post some screenshots. I've done this with the same exact procs / buffs every time, there was no variation of anything.
1. Cast corruption on target dummy, now when you get procs, recast corruption and note the damage.
2. Cast corruption on target dummy, now when you get procs, cast fel flame. Note the damage. It will be much higher then when you casted corruption again.
3. Get procs with MG before dotting, cast corruption. Note damage. It should be at full power.
Edit : Here is another screenshot to better understand it with my combat log