When you try to place blocks where a floating marker armor stand is, only certain blocks like redstone, string, or fences can be placed. All other blocks flash briefly and then disappear.
Steps to Reproduce:
1. Run the commands
/summon ArmorStand ~ ~ ~ {Marker:true,NoGravity:true}
/summon ArmorStand ~ ~0.0001 ~ {Marker:true,NoGravity:true}2.You can place a stone block in the 1st armor stand, but not in the 2nd.
3.You can place redstone in both armor stands.
Environment
OS: Windows 10 64 bit
Java:1.8.0_25
Intended, if the solid part of blocks being placed is in a entity, it fails to, redstone for example isn't solid, fences don't occupy the full block, so there is a rather big chance you don't place it on the entity.
Marker armorstands still are entities and occupy the space, this is intended