Shortcuts not working

I am having issues with the keyboard shortcuts on my PC. In the past I've used "enter" to create a system break, and when typing lyrics, "enter" to start a new verse below. Both functions have not been working. I have gone into preferences>shortcuts and reset the system break to be "enter" even though that's what's already there and it will work after that for a day or two, but it won't let me change it for lyrics because it's already assigned. These aren't shortcuts I made up, but what I've used for years as the built-in shortcuts so I'm not sure why they have stopped working consistently in the past month or so. My version is 4.3.2 so as far as I can see I don't have any updates. Am I disabling something without realizing it? I'm puzzled.