Mansion in the mists

Draiocht hengestones needs to be activated to access "Mansion in the mists" map.

I have completed all surrounding maps + clicked on appeared Hengestone.
Mansion is not accessible.

Now some already completed maps are shining blue - Map attempted. I have rerun them (several of them few times) complete + click Hengestone.
Mansion is not accessible.

Those maps again shining blue (Map attempted) - I have rerun them (several of them few times) complete + click Hengestone.
Mansion is not accessible.