I have a similar issue with mine but haven't had a chance to fully debug it. I put the game into gofer test mode and let it cycle for an hour--absolutely 0 failures.

In game I seem to hit this randomly maybe 20% of the time. I was actually starting to think that it's a software bug ("accidentally" activating the catch release magnet), but then I noticed that there seems to be a correlation between the gofers "talking" and the ramp not staying up...My theory is now that perhaps the quick up/down motion during talking causes the catch to miss occasionally (perhaps due to a malformed catch, etc.).

Mike: Did you find that your gofers worked flawlessly in test mode but not in game mode?