I had sometjhing like that happen with the bluetooth trackpad I use on my MacPro. For some totally inexplicable reason, the settings had all reverted to the defaults.

Any ideas on how to fix it?

Then check default settings.

I did not see an option for default settings.

BTW, it's a laptop, so no batteries.

Don't know why that would be so, but we seem to be back on *track*, lol.

When my trackpad went crazy I had to reset something to default. Not in preferences, but to the computer itself. It was done with a mnemonic key press that I can't recall. (CMD+CTRL+D+R or some such.) <----example only

I am thinking it might be something as simple as a seed caught underneath it or something.

The earlier MBPs with the removable battery had some issues with the battery swelling just a tiny bit. That put pressure on the underside of the trackpad causing erratic behavior. The fix was to remove this tiny rubber wedge that was there to keep the battery from moving.

Yes, it could have been something as simple as you describe. I am also told that wet (sweaty) fingers can cause it.

Weird.

will see if the problem recurs if the battery heats up again.

I was also eating cheetos and kept licking my fingers, so that could be the problem as well (just kidding).