I had three opponents left in a 2-1 split. Onatel’s special was on the one with 1 turn left, and Onatel was charged. Hit the 2 with her special. The next turn all three lost her effects when only one should have.
None of their heroes had cleanse, and the initial effect was applied to the 2. Seems like when the counter reached zero of the one, the logic removed the effect from all.