Necropolis Mapping Blocked Area POE2

I am playing POE2 Mapping System in the end game (T15 + 1 Monsters Level + Ritual) in Necropolis Map.

I am facing a problem where there is an area that is unreachable at all and there is a Rare monster which is mandatory to complete the map.



This is the Whole Map:



This is the specific blocked area:



I lost 1 Divine due to this bug or whatever it is LOL.