Great but I Cant Finish Due to Glitch

I got through the whole game, except for when you have to flip all the marker switches but the one on the dock...which means I have to flip the one by the clock. I was able to flip it up before, but now I cant flip it back down. Theres some wall or something that wont register that Im close enough to work the switch. I can technically finish it by using a walk through, but this really bummed me out...it needs to be fixed otherwise anyone trying to complete the game without a guide wont be able to.

Afyjongtvdkgfh about realMyst