/locate and Eye of Ender pointing to wrong location for stronghold

Seed: -9198315552835156374

"/locate" command yields: "The nearest stronghold is at [8,~,8] (### blocks away)"

Eye of enders lead to same position. 

Enter Spectator mode and see that there is no stronghold at [8,~,8].

http://chunkbase.com/apps/stronghold-finder#-9198315552835156374 shows no stronghold at that location [8,~,8]. 

Strongholds DO exist in at least one location, found by chunkbase.com. Found stronghold at [1540,~,-380] and verified with Spectator mode. 

World was generated on a server during updates but before full 1.13 release and is now running on the full release 1.13.1.