The META can hold an entry for a region with a different server name from the one actually in the AssignmentManager thus making the region inaccessible.

RegionState rit = this.services.getAssignmentManager().isRegionInTransition(e.getKey());
            ServerName addressFromAM = this.services.getAssignmentManager()
                .getRegionServerOfRegion(e.getKey());
            if (rit != null && !rit.isClosing() && !rit.isPendingClose()) {
              // Skip regions that were in transition unless CLOSING or
              // PENDING_CLOSE
              LOG.info("Skip assigning region " + rit.toString());
            } else if (addressFromAM != null
                && !addressFromAM.equals(this.serverName)) {
              LOG.debug("Skip assigning region "
                    + e.getKey().getRegionNameAsString()
                    + " because it has been opened in "
                    + addressFromAM.getServerName());
              }