ping reverb ??HELP

[jazzmaster]

Hi
I built the PING REVERB pedal a while ago, it worked fine.
But the signal was not the cleanest. So after I assembled the module I had to disassemble to measure voltages. I have attached pictures that show that there is a voltage that should not be at resistors 12 and 13.
I tested voltage Vcc and Vb. I checked that the ground in different nodes shows zero volts between them. The values are fine. Only the output of the module shows 0.5 volts when it should be zero volts.
The only thing left is that maybe the 3BDTR-3H module is incorrect.
Anyone have any suggestions?
Thanks