Just a little background: I only play on zombie maps these days. Without zombies the game is way too happy and care-free. Zombies, as well all know, make everything better.
Naturally, I've been experimenting with automated defences/ zombie removal devices. You don't want to rely on your military to kill zombies, not with the insane re-animation rate.
The trouble I've been having is with pressure plates + animal triggers. Either war dogs or pigs which will run across the plates when the spot zombies, retracting bridges which drop zombies into lava. They are leashed next to the pressure plates, and their movement is predictable.
The trouble comes when the animal runs across the pressure plate too many times (pigs will panic and run back and forth across it), or when multiple creatures stand on the plate.
At these times, bridges will (with alarming regularity) lock in the "OFF"/"bridge usable" position. This is very pleasant - if you're a ZOMBIE, because it means FREE DWARF BRAINS FOR EVERYONE!!!
I'm now considering doing away with pressure plates, and using manual levers for everything.
It's safer (fewer unintended lava baths) and it's reliable - pull the lever, stuff happens!
Am I right in thinking this is a known bug? "ON" signals get lost when they come too close to an "OFF" signal? Or signals having to be in order? I.e. "ON, OFF, ON, OFF" works but "ON, ON, OFF, OFF" = locked bridge, everybody dies?
Really starting to pull my hair out with this one, because without reliable working pressure plates, my whole defensive strategy is ruined, and if I can't kill the zombies, my FPS tends to zero quite quickly...