Six weeks and it lost 10 lbs, seems reasonable. I try not to go more than a week without checking pressures and I seem to need to add air about every two weeks.
That said, what is the recommended pressure for your front tire? My R3T is 36 I believe, so if you're going all the way to 41 then that says you were only down to 31. If so, its a bit surprising that 5 lbs below recommended pressure would have that bad a result unless of course 41 is your recommended pressure.
Hope it solves your problem.