Often, after depressing the ptt key, TX stays ON, and I have to press and depress again to get back to RX. I first think about a bad SWR which could give troubles in the usb wire going from the computer to the USB/I2C module of the Softrock, but even without power output, I get this problem. Why not to double the order given to go back to RX from TX state ? ....
I do not have this problem with my FA-SDR. Both the hardware and the button PTT work as exspected (version 3.6.13).
Only when some time ago I was operating the FA-SDR with an endfed half wave antenna (Fuchs antenna) with its high voltage end close to the SDR the PTT operation was irregular and it looked as if the 5 W PA Amplifier was oscillating and the HF leaked into the usb CABLE.
I noticed, when trying to tune the variable capacitor of the filter for maximum output power, that oscillations started when coming close to the tuning knob. The problem was solved by moving the front panel of the SDR away from the capacitor and extend its metallic axis by a plastic cylinder ( 6 mm diameter). Another solution could have been to operate the SDR away from the antenna. "PTT troubles" stopped also when connecting a dummy load to the PA instead of the antenna.