Sanwa m12 voltage issue

[Mx45]

Hi just seemed to of found an issue with my Sanwa M12 it shows the incorrect Rx voltage I'm running the correct reciever as supplied with Tx and I am using the telemetry to keep an eye on voltage and motor temps, however the display seems to only be showing Bec voltage and not battery supply voltage yes I'm running it with an esc (tekin rs pro) can this be rectified or am I wasting my time. Many thanks in advance.

Paul