Hi, welcome. I can't be a lot of help with this, but maybe someone else can give you some in site. Is it happening at the same time in the night? Can you find any kind of common denominator? My first thought was that maybe she is getting a mild shock from the heating pad. It could be so slight that you can't feel it and also perhaps she only feels it if she is laying in a certain spot. Would it be possible for you to get her a new pad? How strange, I hope you can get it figured out.
