Yes, the tx voltage is on during receive, and will be very close to the supply voltage.
Hans has given a good description of why this is done; it helps receive work better.
It is turned off when entering the diagnostics tool, so you can see a near-0V value in receive, and its full tx value during 'T' tx test.? It is turned back on when exiting that tool.? This is a good way to test Q507 - because if Q507 is broken, it won't go down to near 0V.
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Having the tx voltage on during receive is normally not a problem for the PA.? The TX signal is off, so the PA driver and gates of PA transistors are off.? It should only be an issue if there is something shorted/failed in that circuit (the BS170s or driver chip).
