Letters getting inserted randomly as I type. Has this ever happened to anyone? I have a 2014 Retina MacBook Pro with Mac OS 10.12.4 and 16GB of RAM. Everything was fine until a few weeks ago when I started to notice strange behaviors:


The "e" and "t" characters in my keyboard randomly stop working and start working again in a few seconds. In the time that it doesn't work, if I hit "e" a few times to get it to work, it collectively adds all the "e's" in some other part of the text as I type. As far as I can tell, my SHIFT or other keys don't appear to be stuck, I didn't drop any liquids on the laptop or change any settings.
Spotlight used to work great. Now, when I type an application's name, it works sometimes and not other times. I checked Spotlight settings and it looks like Apps are enabled. I can barely find what I want with Spotlight anymore.
I usually sort my files by "Kind" in Finder. In the past, it would organize PDFs separately, images separately etc. It doesn't anymore even if I set it to "Kind".


I'm not sure why it's starting to be buggy. My laptop hasn't fallen or anything. It's on my desk all the time. I've never really had to reset it. Could it be that it has a lot of junk files accumulated from usage? Anyone else experiencing these? What can I do?
Yes this happens due to several causes. USB hub issues (there are several internal “hubs” that can fail - liquid damage is a likely cause, but not the only one). Connecting faulty or failing usb and Bluetooth input peripherals is also a likely cause until you rule that out. 

Lastly, software automation could be a far less likely cause. Booting a brand new OS on an external drive might be a good way to check for that rather than erasing and reinstalling your Mac.