Was making the compact villager trading hall by szpeddy which uses detector rails side by side (but not connected) in a stationary position. Noticed that the villagers can "walk" in the minecarts, moving them slightly off track, but not completely. This created an environment where the villager was able to press two different detector rails at the same time. I got into the minecart and moved left or right and the same happened. I imagine this can happen with any mob. This was possibly intentional, and if it was then it's a farm breaking mechanic that doesn't seem necessary.