I am attempting to use HydroRIVERS data to extract all river outlets into the ocean. Based on the technical documentation, I believe this could be achieved by selecting all records with NEXT_DOWN=0 and ENDORHEIC=0. This approach appears to find all of the points I am looking for, but it also finds a cluster of river-ends in Central Asia (mostly around the Kazakhstan-Russia border, extending into Mongolia) - see image below.

Is this a mistake in the data, or am I incorrect in my assumption that NEXT_DOWN=0 and ENDORHEIC=0 means the river reach meets the ocean?