Updated this issue. I have noticed it to be more general. Two layer thick snow blocks I had on top of a roof turned into (only graphically) water source blocks and fire. If I step into it just glitches around like the snow slabs were still their. I would never actually take fire for water damage.
I am not sure if this is fixed in the latest snapshots or if this is a duplicate issue.
I have also seen a few YouTube videos of torches being replaced by water source blocks.