Mine has been doing this recently.
I’ve been suspecting a partially blocked Vaporizer as it seems to be regenerating more often. I noticed any time I pull up at home that the idle hunts ever so slightly and my exhaust temp gauge sits over 300c. If I let it sit idling the engine note eventually quietens and the exhaust temp falls.
I checked the Vaporizer fuel line with a vacuum line and it holds some vacuum so it’s partially blocked.
Just waiting for time to attempt to remove it and check it out.