I rather suspect Network Rail had a bit of a panic, when they objected on the basis of a crossing that apparently is so serious in terms of unmanaged risk (and they described rather a lot of incidents and predicted future incidents), told all that to the track access part of ORR, seemingly forgetting that other parts of ORR (e.g. HMRI/enforcement) would also see that statement, and rather quickly identifed that there is clearly an unmanaged risk there that they may not have been aware of previously!
Better fix or mitigate it, quickly - regardless of open access!!