This is the current waveform of the switch and the Vds of the MOSFET.
Ideally, the current should fall off in a normal fashion with the switch turns off.
Here, the current fall stops and becomes flat for some time and then falls again.
Unfortuinately, the flat current here is flowing when the switch is operating in the active region and resulting in huge power losses.
Any views here as to why this is happening?