Strange arduino bug---code garbling

I suffered a strange bug recently where all of my comments were garbled somehow in a regular way. Let me explain. Everywhere the letter "c" appeared in my comments, it was replaced with something else following:




thus "calculate" becomes "va1lculate", "oscillation" becomes "osvi1llation" and so on, all throughout my code, as if a script went through and did it. It couldn't have been a find-and-replace on my part, because I have no idea how to replace one character with 2 characters that include some of the original string between them. This was very annoying requiring me to go through my code and change practicalyl every comment. It does not seem to have effected the code because it compiled.

Any ideas how something like this could happen?

I've seen that happen when cutting and pasting code from outside the IDE into it. I closed the IDE and re-opened it. The code displayed fine, then.

In this case it was saved in the file--I opened it with kate to check--and I developed it all in the arduino ide, especially my comments.