My understanding is that with single-NDIR sensors (like the MH-Z14 and 19), the auto-calibration is intended to overcome gradual particle buildup and beam degradation in the sensor chamber. While disabling it will prevent the scenario I described, you'll instead end up with gradual sensor shift as the sensor ages. I guess this could be minimised by manually calibrating the sensor outdoors on a regular basis.
Dual-NDIR sensors split a single beam into two chambers, so any degradation of the sensor beam affects both measurements, and the particle buildup in both chambers should also be approximately equal over time, so they should remain accurate over an extended period without any requirement for calibration. I built mine about 4 years ago and I do occasionally check to make sure they read ~400ppm when placed outdoors, last check was around 420ppm which suggests they're behaving reasonably well as they age.