1 x 1 bubble columns won't form even when neighboring blocks aren't air

When placing a magma block or soul sand under a vertical 1x1 column of water bubble columns will fail to form unless some of the neighboring blocks are water blocks. See attached image.
EDIT It appears that this bug might be related to bubble columns also not forming in 2x2 water column formations even with water blocks present. In the two images the bubble columns appear to only form in the North East and South West water streams.