Did you change any other gear at the same time? My wife, daughter and I all dive on Luna's and the only issues I've had with the transmitters is with various lights and strobes. When use the smaller Ikelite strobe (DS51) it would interrupt the signal, the DS160's will only do it if I hold it right ontop the SOL unit. Underwater Kinetics lights do it if they're in the same hand that's got the unit on it, but not in the opposite hand. I mounted the wrist unit on the strobe arms of my camera (now with YS-D2's) on it and the first two dives it was fine, in the third dive of the day it started to get cranky and lost occasionally (likely the D2's were charging slower from slightly depleted batteries).
-R