panic in go_xdcr.log while running high bucket density test

2019-01-01T22:56:33.944-08:00 ERRO GOXDCR.XmemNozzle: xmem_de729116c99d5a3d3552c8e4deff1d21/bucket-19/bucket-19_172.23.96.16:11210_1 Received temporary error in setMeta response. Response status=TMPFAIL, err = <nil>, response=<ud>MCResponse status=TMPFAIL, opcode=0xa2, opaque=9634587, msg: </ud>

2019-01-01T22:56:33.944-08:00 INFO GOXDCR.StatsMgr: de729116c99d5a3d3552c8e4deff1d21/bucket-10/bucket-10-623320309 message

2019-01-01T22:56:33.944-08:00 INFO GOXDCR.ReplMgr: checkReplicationStatus exited

panic: runtime error: invalid memory address or nil pointer dereference

[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x71a578]

goroutine 54 [running]:

expvar.(*Map).Get(0x0, 0xa3b4a2, 0xe, 0x0, 0x0)

        /home/couchbase/.cbdepscache/exploded/x86_64/go-1.8.5/go/src/expvar/expvar.go:150 +0x38

github.com/couchbase/goxdcr/pipeline_svc.updateStatsForReplication(0xc42094aa80, 0xc4a9fb16e0, 0xcc9a20, 0xc420146e00, 0xc420132ed0, 0xc4201503c0, 0xcd27c0, 0xc420172028, 0x3, 0x0)

        goproj/src/github.com/couchbase/goxdcr/pipeline_svc/statistics_manager.go:1347 +0x173

github.com/couchbase/goxdcr/pipeline_svc.UpdateStats(0xcc47a0, 0xc42014e9e0, 0xccba80, 0xc420166930, 0xcc9a20, 0xc420146e00, 0xc420132ed0, 0xc4201503c0, 0xcd27c0, 0xc420172028)

        goproj/src/github.com/couchbase/goxdcr/pipeline_svc/statistics_manager.go:1248 +0x34f

github.com/couchbase/goxdcr/replication_manager.(*replicationManager).checkReplicationStatus(0xcfeae0, 0xc420071110)

        goproj/src/github.com/couchbase/goxdcr/replication_manager/replication_manager.go:358 +0x312

created by github.com/couchbase/goxdcr/replication_manager.StartReplicationManager.func1

        goproj/src/github.com/couchbase/goxdcr/replication_manager/replication_manager.go:166 +0x4ae

[goport(/opt/couchbase/bin/goxdcr)] 2019/01/01 22:56:34 child process exited with status 2