I'm pretty sure this has happened since upgrading to 4.0c RC1/2...but I can't say 100% for sure since I haven't done any inductive highlighting for about a week. I opened my Isaiah inductive layout this morning and discovered huge sections of extra highlighting that I know for sure I didn't put there (nor did anybody else in my household).
99% of the yellow highlighting shouldn't be there...and there are several random sections that look like this:
