My bad, I apologize. Corrected update: Minecraft 1.9.1 Pre-Release 2 affected version.
Still not fixed as of version 1.9.1 Pre3Horses being lead with a lead are unable to travel up hills and elevations 1 block high.
This issue is Not fixed as of version 1.9 and 1.9 Pre3.
Michael R Jones
My bad, I apologize. Corrected update: Minecraft 1.9.1 Pre-Release 2 affected version.