I used the Lens of Time on a foal using 25% off token. After returning to the barn, I noticed a little more money was missing than usual, so checked my accountant, and found that it had charged me twice. I went back and checked and found that my other 25% off had also been used.

I want to stress that I didnt refresh the page, press back or do anything to give it a reason to charge me twice. Im not entirely sure whether this is a bug or not, but thought its best to bring it up in case it is and causes other problems.