I'm not 100% this is a glitch but I've zapped my pet three times today and every single time this is what I get: "The zapper was pointed right at your pets minion, but it doesn't have one!"

It just seems odd that out of however many combos of random things I could get, that this one keeps happening over and over. Is anyone else having a similar problem?

I think that should be just bad luck, there are a lot of cheap minions you can attach to your pet though, as some of the zaps aimed at minions turn them into a valuable items, some are stat boosters :)