Try rotating the House Code and Unit Code wheels and then reset them to what you want. Sometimes the switches can get dirty and the codes change all by themselves.
That was my first thought as I have seen that here on a lamp module. However, examining the codes:
H2: 1101 11100 (transmitted)
E5: 0001 00010 (received)
G14: 0101 10000 (received)
The switch contacts pull the input low. So, a dirty switch can cause a bit to become a "1" when it should be a zero. The errors seen here cannot be explained by a dirty switch. For example, G could become H, or E could become H, but H could not become either E or G due to a dirty switch.
The fact that the unit code was also being effected rules out a bad switch. And, because a dirty switch on the transceiver would cause it to also listen to a different housecode in the RF link, the H remote would be ignored.
I also considered the possibility of a collision if a TM751 shared the same housecode as another transceiver. A collision could occur if the RF signal was marginal, and was picked up by the TM751 slightly later than the first transceiver. It would then begin its transmission while the other one was already in process. However, a collision almost always results in the command being ignored by all modules. I suppose it is possible to come up with a bit alignment that might morph one command into another, but I haven't sat down with some graph paper to check that possibility.
In my testing I have certainly seen noise sources morph comands from one to another. It is pretty easy to overlook a simple charger for a new cellphone or MP3 player. As you can see in that report, that little Cellet charger is one nasty device.
Of course, it could be a transceiver that is starting to act up, and will eventually have to be replaced.
Jeff