Walking on farmland will push a player off the side onto certain blocks. Opened a test world and discovered that farmland will push a player off onto any lower block, such as the following that I've tested for:

• Anvils
• Half slabs (top or bottom)
• Stairs
• Fences
• Bells
• Trapdoors

Also noticed, while testing that it will push off onto the following full blocks:

• Glass
• Leaves

I figured I would test for other transparent blocks as well, but so far, sea lanterns and glowstone, etc, are ok.  It seems not all transparent blocks are causing the issue.