Odd for sure! It happens no matter what is open. Using the Alt key has no effect on what's in the clipboard, if that helps. And there is no problem with the Alt key by itself.
Same effect on my USB keyboard, but I mainly use the MS keyboard (it's either the Web version or Multimedia version, it doesn't say on the keybrd).
PS: I'm going to be down for a while, gotta add a new drive to replace C drive and a few other updates and the like
)