Absolutely. And who knows if it's CPU related, or maybe something else. If they happen to use a PC that can run the level I created at work, then I have a bridge that's under k. But they might have one that's like my PC at home where that bridge fails every time, in which case I can't send in my best bridge and would need to send in my current "safe" best, which is k. Because I don't know whether their machine will accept my cheap bridge I'll need to go for the safe bridge

People who happen to have a PC like my one at work where riskier bridges work might send in their bridge, but if ChronicLogic use a PC on which that bridge breaks, then an otherwise valid entry will be failed!
Controversy! Someone phone the tabloids 
Or there might be other physics variations between PCs that cause even my "safe" bridge to fail!
For what it's worth the part of the bridge that's breaking for me are the very small links inside the deck joints which a cable connects to. They seem to be the weak point in my bridge compared to all the other components. At work they are very close to breaking but don't, but at home they are snapping.