Survey Grid use this speed issue

I recently noticed on a number of builds to that I tested that the use this speed option does not work.
I run a test flight on 3 separate builds and wanted to us 1m/s speed just so I could see it in action. Set the speed on auto mission options, checked the box in order to use it and it did not work. What I noticed is that it was always using the preset wp navigation speed.
@Michael_Oborne have any other people reported this or am I doing something wrong? I have tested this function in the past and it was working flawlessly.