Q: Apple Keyboard inserting "5" randomly

This is not related to Magic Mouse or Trackpad, but that is where the support page took me when I selected my issue and I couldn't find a community that I was able to post in that seemed more relevant.

I have a strange problem: When using my external Apple Keyboard (the extended one with the numpad, model number A1243), it occasionally inserts a "5" after I type either "i" or "o". This makes it impossible to use normally when typing just about anything.

I did some research and think it's most likely due to a short somewhere in the keyboard, and using the keyboard viewer I found that it presses the 5 key in the numpad. I know this is a hardware issue with the keyboard because it behaves the same way when I use Windows through Bootcamp and on a different Windows PC, however it does not occur when plugged into my Android phone or tablet (probably because they don't have the numpad enabled by default). I tried disabling the numpad with the Clear key (as well as Shift+Clear and Option+Clear) but it still works (at least in macOS). I also tried disabling it by enabling Mouse Keys in the accessibility settings, but that wasn't much better because the feature uses 5 as a mouse click.

So what I'm asking is: Is there a way to disable either that specific key or the entire numpad so that the 5 stop appearing, or do I have to take my keyboard and see if the underlying hardware issue can be fixed?