What are you smoking it on and where the heat sensor is may be throwing you off. If it’s dang cold where you are at and your smoker is stamped metal, without a heat blanket, the sensor may be reading 225 near your heat source, but the meatloaf is sitting in a spot much cooler. When you bring the temperature up 50 degrees, it might be 275 near the sensor, but at 220 where your meat is. Cold weather really is tougher to navigate with some cookers. When I had a Traeger and the temperature was below 30 it was going to be a long cook, using lots of pellets. I did get a welders blanket eventually and it helped.
My only other thought is that your gauge is off. Is it factory? You can check by boiling water, stick the sensor in the water and see if it reads the boiling point for your elevation. If it’s off, just note how many degrees it’s off for future cooks.
Good luck! Looking forward to hearing more details!