Custom Report Default State doesnt work?

Hi there

I'm not sure why our Custom Report behaves this way but it doesnt seem to take a default state. 

I've tried setting it multiple times within Data Sets. However each time I come out and back into the App it just goes to a couple of fields I once selected weeks ago and nothing else.

It only ever shows the default state I want when I go into Edit mode and hit the "Show Default State" button. Which means its kind of useless as a default state for users.  

I've checked bookmarks and we have no default book marks.

Its pretty confusing that whenever we go to custom report it always shows pretty random fields as default.

Is there some other override anywhere else? 

Is this a known bug?