Constant troubles with Descent T1 Transmitter

Hello
have you had as bad bad experiences with the Garmin tank transmitters as me? I bought 3 of them. The were all replaced by Garmin once in the meantime (at least that works). The last one always showed 8 bar even when disassembled. Consequently, it no longer went into standby and constantly had a dead battery.
The replacement transmitter then worked fine for a few dives (about 20) but now it starts losing connection all the time. It also seems to me that the frequency is increasing. In the beginning, the yellow indicator blinked from time to time, but now the message that the connection is gone appears more and more often.

The connection is re-established shortly after, but honestly - that can't be it! On my Sidemount set it started like that, too. 

It then ended up with them loosing connection and randomly re-establishing - or not.
I ask myself slowly whether it is not perhaps also on the clock. I now have 3 pods that all show similar problems.