As some of you may know, I have recently had a game become glitched beyond return (for some reason it "remembered" code I had deleted during play), and I determined there was something wrong with its file. I tried to save it, but I ended up copy-pasting the code into a new game. I'm not sure what the cause of it was.

I use the online editor.
Was it me? Was it decay? Will this happen to my other games?

Edit: It happened sometime after the 5.7 update. Not exactly after, but sometime after.

It's this game. This is the father of my other game. (Which is the son of a gamebook...)
http://textadventures.co.uk/games/view/0p9uxrxu2ueatixrnt1ixg/pokemon-type-harley-johto-and-sinnoh