North East Rover - Northumberland Line validity?

Is North East Rover valid on the Northumbria line to Ashington?

Yes, per Northern's website's map.

Looking at the map, it looks like Castleford to York direct services aren't covered, although I'd be surprised if it wouldn't or shouldn't be accepted.

Half way through my second 4 in 8 of the fortnight. Did Ashington this morning and Manchester to York via Castleford last week. Both accepted with no question. I think both are intended to be covered, but some of the industry maps are just wrong/out of date.

I would imagine the maps simply haven't been updated to include both the Ashington line and the hourly service between Castleford & York. Similar to around 2014 time when TPE diverted the Scotland - Manchester services via Wigan North Western & the Eccles line, how long it took for the Lancs Day Ranger map to get updated to include that curve as previously it only had a limited service. Back when Wigan had a fast service to Manchester