Iron golems failing to jump up single blocks

When iron golems navigate the village, they are able to walk down a single block without a problem. However, they refuse to walk up a block, even if I have them on a lead. This occurs on gravel, grass, and path surfaces. The problem was first noted in 15w46a and has persisted into 15w47. I have not been back to this village in 15w49, so I cannot confirm that the snapshot is affected by this issue.