Solved
Three nut glitch!
I was playing an opponent who played a three nut which gives any plant played an attack of three. I bounced two of their nuts and eventually destroyed the three nut, but when they played those nuts again, the nuts still had an attack of three, but usually when any card is bounced it gets reset to its normal settings, so those nuts should have been reset too!
In the first screenshot, the nut in the heights lane had just been replayed, and in the second screenshot (which was actually the round before the first screenshot) the water chestnut had just been replayed.
[Do not upload images containing other players information - CM]
