UV-5R Mini question: minimum number of channels needed for scanning?

I was messing with my baofeng and loaded up some air frequencies into maybe 12 channels and was able to scan those channels fine. I then deleted all but the first 3 (0, 1, 2) and now when I hold down the # nothing happens.

I can switch to weather and scanning works fine across those 10 channels. Wondering if there is a lower limit I need to satisfy.