I managed to get it working by trial and error, but I don’t know why it works like this.
On WeMos D1 mini it didn’t work on pin D4 and worked on D5.
On ESP32 esp32 devkit v1 (30 pin version) I tried different pins in pulse_counter setting flashing ESP32 each time I wanted to try a new pin. Pins GPIO13, GPIO12, GPIO14, GPIO19, GPIO4… did not work, they went “high” after flashing. Lastly, I tried pin GPIO36 and it worked.
Now pulse counter works fine.
But can you please help me understand, why it works like this? What is so special in GPIO36 pin that it worked?