when standing on fences you hove one block above them

I have the same I'm in android-Huawei Ascend 4.4.4
And you really do hover one block ontop.

I'm 11.1

Works As Intended. The fence's collision box extends one half block above and below the fence texture to prevent player or entities from walking over it.
I recommend checking the Minecraft Wiki prior to reporting an issue on the bugtracker, as what seems to be a bug to you may actually be intended.