Check the back of the keyboard to see if a key has been hit and it's separated the soldering joints.
This seems to happen on really beefy/heavy keyboards when a key gets hit it can do that, but usually just a quick touch up and you're good. If you need to replace switches there are many on here including myself who have some. Just post what you're looking to replace.
I'm skeptical of that hypothesis, because they keys just seem to slowly go bad over time. However, I will check as that is not something that I had thought of.
These are DataDesk Smartboards. They use ALPS simplified tactile clicky, I think, type III or IV.
Are these keyswitches still made by anyone? Or is it cannibalism only to get replacements?
Thanks,
Reid