Comparator side input does not recognize all types of redstone power sources

Reproduce bug: Place down a comparator. Behind the front input (A), place one redstone dust and a block of redstone. On either side of the redstone comparator (B), place a block of redstone. See attachment.

Expected results: Since the the side input (B) is greater than the front input (A), the output should be off.

I don't know if this is intended or not.