Sorry, I down with the flu and not all cylinders are firing.
Hope you feel better! The flu sucks.
I guess my question is, does this happen to anyone else?
This happens to just about everyone that has a skimmer. Chemicals/additives/corals/tank food all have a tendency to reek havoc on a skimmer, causing it to overflow.
Seems like I should be able to mod something to prevent this in the future.
It is hard to prevent it but you can contain it. I am a big fan of the following: Have your riser tube (the tube that goes up into the skimmer cup), shorter than your cup height. This way, instead of immediately overflowing, your skimmer effluent will "leak" back into the riser/skimmer body.
Somebody correct me if I'm wrong, I'm often wrong. 