I was flying today and noticed that the air coming out of the lower central vents (fed by the starboard side scoop, shares ducting with cabin heat) was warmer than the air coming in through the roof scoop ceiling vents. I knew that this vent line is shared with the cabin heat so I immediately suspected that the cabin heat was ever so slightly mixing in. I shut the cabin vent push actuator and confirmed that there was a very small amount of quite warm air coming from the same vent. Is this normal? Any thoughts on likely culprit? Just an issue with the baffle controls in the vent line or something more nefarious?
Thanks in advance!