Hmm, that doesn't sound like what I've had going on. This only happens when I'm trying to shift the chainring while going uphill, or at least it was by far more likely to happen then. And I can't for the life of me recall if it was going from smaller to larger or larger to smaller sprocket.

It's chain drop, no problems shifting except for this. No gear that's hard to get into, no chatter at odd times, as long as I stay out of the crossover gears I'm good for that.

Like I said, the mechanic said it was the opposite of when he would have expected a chain to drop.

My memory is so bad. I guess I'll find out if I ever get to the place where I can do some real riding again, whether or not the chain replacement fixed it.