Z axis resetting zero on find home command

Can anyone tell me why the zero on my z axis is being reset to a new zero on the find home command in a sequence?

I recorded a video of it here- https://www.dropbox.com/s/qhftq8rz7qe9qhn/Z%20axis%20zeroing.MOV?dl=0

What do you have your encoder scaling value set to in Device under hardware?

it is set to the defalut 5556