Damaged RuuviTag?

I have a bunch of RuuviTags, all 18 months old. I noticed that one of them stopped broadcasting. When I put in a new battery, it started working again. But it seems too soon for the battery to run out. Then I noticed there’s something like a burn mark next to the main chip. See here. Could it be slightly damaged? For comparison, this specific RuuviTag is on my balcony, some others are inside, and one is in the fridge, only the one on the balcony has the issue. It’s mounted on a box, so it should’ve never soaked in water, and it has experienced temperatures from 0°C to 60°C give or take, I think these are all within the specifications.

It is possible that there has been some condensation which has caused higher than usual current draw which leads to short battery life and even the burn mark. Please send a message to sales@ruuvi.com, link this post and we’ll figure out the next steps.

That looks like water damage to me. Particularly the small blueish deposits near the burn and round the chip on the left.