Weird keyboard problem on new Lenovo laptop [View all]

Running Win10 Pro.

Starting a few days ago, every time I hit capital B or capital T, I get BT. When I hit capital N or capital Y. I get NY.

Lower case letters are not affected, nor are any other keys as far as I can tell. I can't see anything weird in the keyboard settings, and there doesn't appear to be any grit in the keyboard (and why would it affect only the capital letters anyway?)

Other than the relative positions of the keys, I can't see any connection. Rebooting doesn't change anything.

Any ideas?

P.S: Just now noticed a single ? or { also gives me ?{