Player 1: Plays Dune Scorpion along with a power-up (Momentum/Chaos Power/ Blessing)
End of turn: Scorpion attacks, Player 2 has a -1 additional HP (yellow skull displayed next to HP)
Player 2: Plays an upgraded Purify (or at least 2 unupped Purifies)
End of Turn: Player now 2 has +2 additional HP (small
next to HP)
Player 1: Does nothing, lets the scorpion attack
End of turn: Player 2 has +1 additional HP (and still
is shown at HP)
Player 2: Bug here: Though Player 2 is still in purified state (at least
icon suggests that), by playing cards the player poisons himself and the extra HP status can be turned into a negative range.
I don't know whether the effect is intended or not but there is a bug in both cases.
If this behavior is not intended: Extra poisoning for each played card should not happen until the additional HP goes under zero and the yellow skull appears.
If this is the desired effect: The small
next to HP should turn into a yellow skull as soon as the scorpion bites. Or into something else that indicates that the player is poisoned despite of the current positive extra HP status.
Edit: Can be reproduced in 1.271 so changed to confirmed
