There was an incident involving a walker following a non-existant path north of Causey Pike recently - https://outdoorsmagic.com/article/ne...avigation-app/
Having done a bit of a search the claim that OSM data is incorrect is in fact incorrect, the underlying data does not have a path in that area, here's what it looks like: https://www.openstreetmap.org/#map=17/54.57688/-3.21227 so it's more likely that the app in question has added it in some manner.
I checked the Strava heat map and there's no MTB activity there but quite a lot of running lines - https://www.strava.com/heatmap#16.00....58215/hot/run (Causey Pike is the hot bend left of centre at the bottom of the screen).
There's a lot of running lines heading down and across that fellside which got me wondering if there's a race that goes that route. Is that the case or are these just lines from training runs? There are no Strava segments in that area to indicate anything either way.