Either you have a severely leaking injector(s) or the thermostat's bypass spring has gone soft and is opening anytime the engine is off idle thereby not allowing the engine to run warm enough to get off of the richer warm-up map and causing the truncated regeneration cycles. Replace your T-stat with a Stant 48808. Also, be prepared to make your own T-stat gasket as I've had a hard time getting the factory gasket to seal correctly, so I'm using thicker gasket-making material and making my own thermostat gasket for my Kioti's engine. I take viewers through the whole process of swapping T-stats in one of my videos.
Anyway, for whatever reason, I've observed loader work is hard on the thermostat's bypass spring and in 800 hours, I'm on my third T-stat having just replaced it again just this last spring.