It's just a matter of time and more diving...
I have had two PPS transmitter failures over 12 1/2 years, 1814 dives, 1915 hours. One was an unknown hardware failure and the other was the over pressure release valve
Question - Pelagic Pressure Systems or Shearwater (the Swift) transmitter failures
I have dived a backup computer and SPG during this time period. I have never lost a single dive or a series of dives. I have used my backup SPG on 17 dives, 0.94%
My backup computer has been a Teric since May 2019, 474 dives. I have had two transmitter antenna failures during this time. I did not need the backup SPG as my other computer, an Oceanic VT3, is also AI and running off the same transmitter.