I'm using Word 2016, and, for the first time, it occasionally jumps my cursor when I try to italicize. I have never set any of the options or preferences differently than what it came with: I simply hit CTRL + I and try to italicize. Sometimes it does, but other times my cursor jumps inexplicably to another point in the document. Can anyone help me?

The computer is brand new. There are no sticky keys. Unless its a mouse problem...?