Seems to be working correctly with this beta on the following image (max>min)
identify -verbose image.png
...
Depth: 16/8-bit
Channel depth:
red: 1-bit
green: 1-bit
blue: 1-bit
alpha: 8-bit
Channel statistics:
red:
min: 0 (0)
max: 0 (0)
mean: 0 (0)
standard deviation: -0 (-0)
green:
min: 0 (0)
max: 0 (0)
mean: 0 (0)
standard deviation: -0 (-0)
blue:
min: 0 (0)
max: 0 (0)
mean: 0 (0)
standard deviation: -0 (-0)
alpha:
min: 0 (0)
max: 255 (1)
mean: 55.0361 (0.215828)
standard deviation: 103.896 (0.407436)
Alpha: none #0000000000000000