Default distance disappears when when filter exposed in block and placed on results page.

I have a location/proximity exposed filter in block. I have set the default search distance to 150 kms.

The block works fine except when I put it on its own views page (the results page). When I place it on that page the default value disappears.

I'm wondering why this happens and how I can ensure that the default value for distance (150kms) remains in the block when used on its own views page.