MacBook randomly loads nothing, while in use

Every now and then (random from what I can tell, but there does seem to be a minimum amount of time between each of at least 20+ minutes), my MacBook Air will randomly deselect whatever App/Program I'm running, and switch to Finder (the app/program does not close, minimise, or switch to a different screen), with the cursor switching to the loading animation. It tends to only happen for a couple of seconds, and I'm able to just click on whatever was running to return to it with no issues, but it does get rather annoying, especially when running something that can't exactly be paused, or is not a good idea to pause. From what I can tell, no application or program starts up, but I can't be completely sure of it, as it is random and only happens for a short amount of time, nothing extra seems to open though. I'm not sure when exactly it started happening, but from what I can remember, it too was random. Anyone know what's the cause or what's happening? Would also be really helpful if anyone knows how to fix it? Thanks.