Mosfet Motor Drive amplifying duty cycle of PWM
Thanks to the comments/suggestions provided here, we found the solution. We modeled the circuit in Proteus and were able to recreate the output signal.

Then, as suggested by @G36 the 10k ohm resistor was reduced to 820 ohm, and few minor modifications.

Simulation environment predicted better results:

On oscilloscope too results were verified as true to form.


Thanks to all contributors!