Endermen don't make any check for if they can stand on a surface before teleporting; they only check for a movement blocking material. This causes them to be able to, for example, teleport onto signs, despite them not having any collision. There are also some cases, such as fences, where the block does have a surface to stand on, but because it doesn't cover the full block, they can sometimes teleport to a position within the block that isn't above a surface. The affected blocks, in no particular order, are as follows:

• Fences
• Fence gates
• Iron bars
• Chains
• Glass panes
• Sculk veins (should have the material "replaceable plant" instead of what the currently have, "grass")
• Walls
• Signs
• Banners
• Lanterns
• Amethyst buds
• Lightning rods
• Pressure plates
• Doors
• Open trapdoors
• Conduits

Although adding a check for a surface to stand is likely too complex to warrant its implementation, I would definitely recommend changing the materials of sculk veins to "replaceable plant" and pressure plates, signs, and banners to "decoration," as they have no collision.