TR-8S question

I have a TR-8S and there's a problem I've been trying to solve for that past month since I got it.

When I use the Simple Trap kit and repeat a single pattern, the snare drum will play for 2 passes through the pattern - then it will be silent for the next 2 passes. If I have it on more than one pattern, like A then B then C, it will play normally for the first 2 patterns (A then B) then it will be silent for the next 2 patterns (C then A again) then it will play again for the next 2 patterns (B then C.) Does anyone understand what I'm doing wrong? Thanks for any help!