WP34s Drain battery power

[inaqui76]

Hi all, I'm a structural engineer from Buenos Aires (sorry for my english it's a bit rusty)

I left my WP34s in my office desk drawer when the pandemic started.
It was stored there for almost a year and a half. During this time at home office I was force tu use excel and the phone calculator (shame on me)..
When I finally got back to the office and was able to retrieve it, the batteries were dead. It did not seem strange to me since I did not remembered when I had changed them...
The point is that after 3 weeks it ran out of battery again and I assumed that the ones that they sold me were bad, I replaced them and again with very little use around 3 weeks it ran out of battery again...
Has anyone heard something similar? What could be the problem?