The game is reprogramming the CRT controller for some reason, perhaps to get a few more lines in. CRTs are basically analog devices, so their sync range is pretty much continuous--and they'll tolerate sync frequencies that are pretty far off the "normal" mark.
LCDs are digital devices with a fixed number of elements on the screen and so can attempt to sync to certain frequencies, but their coverage is not continuous.
If you can select other display types in the game, give that a try. Some LCDs are better than others with the old stuff, so you might see if you can try a different one.