Internal load balancer no longer working

[Mike H]

Hi, I have a gke cluster that has an http(s) load balancer, which uses the `RATE` balancing mode as per the docs. I'm trying to expose a workload to App Engine using an internal load balancer. Both services are on the same network. However, when I create the load balancer, I get this error.

Error creating load balancer (will retry): failed to ensure load balancer for service default/internal-es-lb: googleapi: Error 400: Validation failed for instance 'projects/localinsights-staging/zones/us-central1-a/instances/gke-staging-default-pool-85830c52-g6tg': instance may belong to at most one load-balanced instance group., instanceInMultipleLoadBalancedIgs

There are a couple of things that are weird. First, I got the internal LB to work earlier today, and the http(s) load balancer is throwing the same error as the internal LB, even when it's the only load balancer on the cluster. 

Can anyone kindly advise?

Thanks!

[Mike H]

Also, according to the section, "Determining if your Ingress is compatible", the command returned zero entries, so the cluster should be compatible to use both types of LBs.

[Mike H]

I discovered that if I create the internal LBs first and then apply that new instance group to the http(s) LB, it works. Everything is being routed and loaded correctly, but the google console throws errors, so is this recommended or is there some preferred way to handle this?