Inertia single triggers can do the same thing. A soft recoil pad can cause single triggers to act up as well.

I liked those 1100 LT-20s, back in the day. But, I had been bitten by the double bug, and never got around to buying one. I liked the 20 gauge version of the A5 also, and the last time I looked, the prices were pretty high for what they are. More than likely not going to be getting one of those.

Best,
Ted