Woah. Weird. So, first, I tried the keyboard with my PC notebook with the adapter. Perfecto! Without any software...
Then, I plugged the adapter back into the running Mac. The keyboard worked perfectly for about 30 seconds or so in the browser. I stopped typing in Firefox (it still seemed to be working), and I opened Word to test more. By the time I started typing in Word, it was duplicating strokes and slowing down the computer again.
Before (when I first tried the adapter), I had shut down the MacBook, plugged in the adapter and keyboard and then started the Mac. A screen then popped up asking me to press the key to the right of the left shift key and then press the key to the left of the right shift key. I pressed each one time. I didn't use Word the first time.
So, it seems like the keyboard may work natively but some Mac program/script may be messing it up after it kicks in.
I don't know much of anything about Macs. Is it likely that the MacBook is identifying the keyboard wrong and messing up the way it is working? Would there be a way to fix this?
Can I try to redo that process of pressing the keys? I don't think the latter will work as I know I only pressed each key one time, quickly, but I'd try it again if it could help.
I'm just super suspicious after seeing the keyboard and adapter work perfectly for that brief period of time.
Thanks!