OK, so I have my 5 conditional smart search filters and search search dialog (button only) in one panel; these manually trigger a post back search to the Smart Search Results in another panel on the same template. The Search Results shares a web part zone set to use update panel with the non-conditional smart search filter used for the ordering - this is set to auto-postback.
The 5 conditional filters do not auto-postback but the ordering one does - normal behavior for such a scenario. As these are all in the same template using a smart search dialogue I would assume they are all using query string - how else would I determine this as to my knowledge there is no mechanism to set them otherwise.
Could the mixed panels and postback controls be causing the problem do you think?
Appreciate the feedback. The worrying thing from my stand point is the inconsistency not the error and whether this is a bug.