[BUG] Dowsing Device calculation issue
I had a dowsing device active on the field and played a Pludering Pirate, which triggered it to give +3 att. I targeted my Goblin Tomb Raider which was a 2/2 at the time, due to having artifacts on the board. The Goblin Tomb Raider ended up as a 3/2, when it should have been a 5/2. It caused me to not be able to attack on a critical turn during the Arena open, and I lost the match.
[Deleted User] commented
Dowsing Device only gives +1/+0 per artifact that enters the battlefield, not +3/+0, so there's nothing wrong here.