In the early stages it may not always cause corruption, but as the symptoms worsen, so does the corruption. Sometimes it may just be an odd wrong character that is difficult to spot, other times whole chunks of the script may be lost, and sometimes ALL the script is lost.
By now you should know you need to be copying and pasting your script to computer before doing a Save.
So if you are suffering obvious problems every time, try clicking Edit after saving the script, then it will reload the saved script contents back from the ESP and let you compare it to what it should be.
Which all goes to prove that the problem lies with the interpreter cocking up the Save and causing the saved contents to be corrupted - therefore things will obviously go wrong if you try to run the corrupted script, because the damage has already been done.
The boat has a leak, The more you load it, the worse the leak.
Your only realistic option for keeping it afloat is to lighten the load by jettisoning everything overboard that is non-essential... basically your only choice is whether to go down in style, or struggle to stay afloat to complete the journey.