goxdcr panic during rebalance in [goroutine created by TopologyChangeDetectorSvc]

During longevity test, performed failover + rebalance and noticed xdcr stream stopped with errors in logs:

Service 'goxdcr' exited with status 1. Restarting. Messages: runtime.goexit()
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.5.2/go/src/runtime/asm_amd64.s:1721 +0x1 fp=0xc8202547c0 sp=0xc8202547b8
created by runtime.gcBgMarkStartWorkers
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.5.2/go/src/runtime/mgc.go:1239 +0x93
[goport] 2016/03/24 18:30:25 /opt/couchbase/bin/goxdcr terminated: signal: aborted (core dumped)

validateSourceTopology...
panic: runtime error: index out of range

goroutine 464435 [running]:
runtime.gopanic(0x9e04c0, 0xc8200160a0)
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.5.2/go/src/runtime/panic.go:461 +0x3e6 fp=0xc8288b1550 sp=0xc8288b14d0
runtime.panicindex()
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.5.2/go/src/runtime/panic.go:12 +0x49 fp=0xc8288b1578 sp=0xc8288b1550
github.com/couchbase/go-couchbase.(*Bucket).GetVBmap(0xc826eebdc0, 0xc82a9aaf00, 0x3, 0x4, 0x7, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/godeps/src/github.com/couchbase/go-couchbase/pools.go:247 +0x4c3 fp=0xc8288b16e8 sp=0xc8288b1578
github.com/couchbase/goxdcr/service_impl.(*ClusterInfoSvc).GetServerVBucketsMap(0xc8200fc030, 0x7f12a4170750, 0xc820100620, 0xc82064b580, 0x7, 0x0, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/goxdcr/service_impl/cluster_info_service.go:78 +0x297 fp=0xc8288b17a0 sp=0xc8288b16e8
github.com/couchbase/goxdcr/pipeline_utils.GetSourceVBMap(0x7f12a41ae4b8, 0xc8200fc030, 0x7f12a41ae508, 0xc820100620, 0xc82064b580, 0x7, 0xc823158760, 0xc825bf4a00, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/goxdcr/pipeline_utils/pipeline_utils.go:38 +0xdf fp=0xc8288b19a8 sp=0xc8288b17a0
github.com/couchbase/goxdcr/pipeline_svc.(*TopologyChangeDetectorSvc).validateSourceTopology(0xc820310680, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/goxdcr/pipeline_svc/topology_change_detector.go:293 +0x2d4 fp=0xc8288b1b98 sp=0xc8288b19a8
github.com/couchbase/goxdcr/pipeline_svc.(*TopologyChangeDetectorSvc).validate(0xc820310680, 0xbd0000)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/goxdcr/pipeline_svc/topology_change_detector.go:127 +0x55 fp=0xc8288b1d80 sp=0xc8288b1b98
github.com/couchbase/goxdcr/pipeline_svc.(*TopologyChangeDetectorSvc).watch(0xc820310680, 0xc8286f3f80, 0xc823158770)
/home/couchbase/jenkins/workspace/watson-unix/goproj/src/github.com/couchbase/goxdcr/pipeline_svc/topology_change_detector.go:121 +0xd21 fp=0xc8288b1f78 sp=0xc8288b1d80
runtime.goexit()
/home/couchbase/.cbdepscache/exploded/x86_64/go-1.5.2/go/src/runtime/asm_amd64.s:1721 +0x1 fp=0xc8288b1f80 sp=0xc8288b1f78
created by github.com/couchbase/goxdcr/pipeline_svc.(*TopologyChangeDetectorSvc).Start
/home/couchbase/jenkins/workspace/watson-unix/gopr