Geo says I'm at 15 ft depth on the surface

I was diving in Cozumel last week using a Oceanic Geo dive computer. It worked fine on the first day. On the second day, I got it wet getting into the dive boat. It went into dive mode and said I was at 15 ft even though I was on the surface and started logging dive time and wouldn't stop. I pulled my spare and used it. After the dives, the first Geo was still at 15 ft and working on a 6 hour dive so I pulled the battery and let it sit for a day. I put the battery in a day later and it started a new dive at 15 ft even though it was sitting in the kitchen of the rental house. I let it run. Checked it the next morning and the computer had completely shut down. Pulled the battery and let it sit for a while, then tried to restart and it stayed dead. So I pulled the battery again and let it sit for a couple more days then threw it back in. Still dead, so I threw it in a bag and gave up. At the end of the trip I checked it and it had restarted a few days later and reset.

Anyone have any experience with anything like that?

What do you mean that you got it wet getting into the boat?

Sounds like a bad depth sensor to me.

The computer doesn't go into dive mode until it's some depth below the surface (5 feet I think). So if it gets in the water but doesn't start dive mode, it displays "wet".