I am also in a similar situation.
When I press PTT, up to RRC-1258 is recognized as transmitting, but the TS-480 does not enter the transmitting state and remains receiving.
If you connect the microphone directly to the TS-480, it will be able to transmit normally.
From this, it can be seen that this is an anomaly in RRC-1258.
However, if the condition suddenly developed and two other people besides me were experiencing the same symptoms, there must be some fatal cause, so I would like to find out the cause.
In addition, when I output the settings from the RRC-1258 where the error occurred and replaced it with the one that input the settings to another RRC-1258, I was able to use it normally.
Is it some kind of hardware problem?