Master slides Randomly Changing

I am referring to what you see on the network as the .story file. It is not, as you say, a singular .story file, it is a zipped file. I just changed the extension of one from .story to .zip and unzipped it. It is a rather small (1,200 kb, 1 slide, 2 pictures) file, and when extracted contains 16 folders, and 65 files.  I say this to say that any sort of network hiccough, buffering pause, or stray quark flying through your network during the compression/decompression phase can cause enough of a problem to introduce corruption. That's why local saving, then uploading after the zipping (of the .story file as a .story file) is recommended.  Please note that I am not saying the network is for certain the problem, only that it could be. It is possible that changing one slide is not what changes another slide. It might be that the second slide (because of something in the zipping and unzipping and traveling back and forth to the network) is slightly fuzzy, and opening it causes the changes. I'm saying it could happen, and you can't know for sure until you copy the saved file up and down, from local to network, rather than saving and opening directly to the network, and maybe not even then.

Of course, there is no guarantee that I'm on the right track, and there could be other causes that I know nothing about. But I think that's where I would look first. Also, I'd reinstall.