No doubt it is very clear to you as you have created the layout and placed everything in the scene but as the screenshot you posted was my very first view it was as "clear as mud" as to what was going on - which is why you should never do your own proof reading. A close-up rather than the wide whole scene view would have been a better choice.
The "buffer", as you call it, is very unfamiliar to me as ours look very different.
But putting all of that aside, the identities (kuids) of the track and "buffer" would be helpful as the problem may turn out to be with them and not Surveyor.