I’ve recently just had a war match where Ludwig fired so Cupido and Waddles received the mana buff, no issues here.
On the 7th turn after Ludwig fired, Waddles and Ludwig were dead (go me) but Cupido reset the mana gain effect back to 17% gain with 6 turns left.
The other heroes were Phenexa and E&F.
Have I missed something in terms of abilities/passives that mean I should have been aware of this?
Sorry no screenshots as it’s quite a hard thing to capture if you don’t expect it to happen.