minikube: fatal error: concurrent map read and map write

running minikube logs shows the following:

fatal error: concurrent map read and map write

goroutine 274604 [running]:
runtime.throw(0x3ce8ca0, 0x21)
    /usr/lib/google-golang/src/runtime/panic.go:550 +0x99 fp=0xc8246efaf8 sp=0xc8246efae0 pc=0x42f639
runtime.mapaccess1_faststr(0x291e0a0, 0xc82225a840, 0xc820d91fb0, 0x25, 0x589a000)
    /usr/lib/google-golang/src/runtime/hashmap_fast.go:202 +0x5b fp=0xc8246efb58 sp=0xc8246efaf8 pc=0x40e18b
k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache.(*DeltaFIFO).queueActionLocked(0xc821fe04d0, 0x38c58c8, 0x4, 0x3867a00, 0xc82752d700, 0x0, 0x0)
    /usr/local/google/home/aprindle/go/src/k8s.io/minikube/_gopath/src/k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache/delta_fifo.go:303 +0x2e2 fp=0xc8246efcc0             sp=0xc8246efb58 pc=0x110f8e2
k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache.(*DeltaFIFO).Resync(0xc821fe04d0, 0x0, 0x0)
    /usr/local/google/home/aprindle/go/src/k8s.io/minikube/_gopath/src/k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache/delta_fifo.go:498 +0x4f7 fp=0xc8246efe38             sp=0xc8246efcc0 pc=0x1112027
k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache.(*Reflector).ListAndWatch.func1(0xc821547290, 0xc82006cf00, 0xc8219ae780, 0xc8232bd020, 0xc821547298)
    /usr/local/google/home/aprindle/go/src/k8s.io/minikube/_gopath/src/k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache/reflector.go:289 +0x252 fp=0xc8246eff88              sp=0xc8246efe38 pc=0x1127a72
runtime.goexit()
    /usr/lib/google-golang/src/runtime/asm_amd64.s:2002 +0x1 fp=0xc8246eff90 sp=0xc8246eff88 pc=0x464961
created by k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache.(*Reflector).ListAndWatch
    /usr/local/google/home/aprindle/go/src/k8s.io/minikube/_gopath/src/k8s.io/minikube/vendor/k8s.io/kubernetes/pkg/client/cache/reflector.go:296 +0xde3

Steps to reproduce: Unknown at this point, but the number of occurrences has been 3 in the past 2 days.

minikube version: v0.6.0

kubectl version Client Version: version.Info{Major:"1", Minor:"3", GitVersion:"v1.3.0", GitCommit:"283137936a498aed572ee22af6774b6fb6e9fd94", GitTreeState:"clean", BuildDate:"2016-07-01T19:26:38Z", GoVersion:"go1.6.2", Compiler:"gc", Platform:"darwin/amd64"} The connection to the server 192.168.99.100:8443 was refused - did you specify the right host or port? (minikube vm is no longer responsive to kubectl comands)

OS: Darwin Kernel 15.3.0