Oscillating sense current in overcurrent protection
Your circuit is working as intended. It is not an oscillation. Your inductance, L4, is very large so it takes a long time for current to build up, longer than your MOSFET actually conducts for.
Every time you the MOSFET blocks, the current circulates around the inductor through D1 and you turn on the MOSFET again before the magnetic field in the inductor has completely collapsed and the current stops. Since the previous current is still flowing through the inductor when the MOSFET starts conducting again, you continue to build up energy in the magnetic field it continues to increase with every cycle rather than resetting and climbing back to the same point.