Two people using same sourced and tested chem resulting in clear mdma as the active, and on a well known pill... sounds more like one of the players, the non excited recipient s also using other medications then.
If source is confirmed correctly, and measurements etc are all accounted for, only reason one would experience effects and one not is other medications interacting like SSRIs or other antidepressant medication?
Unless im mistaken, only known cause of mdma not working when confirmed to be mdma and not tolerance issues, is antidepressant medications