I've seen the error CannotRemoveRuleUsedByProbeUsedByVMSS
quite a few times now in my Terraform logs, but I've never came around to care enough to actually look into it. Instead, I acknowledged that likely some dependencies are not set up right, shrugged it off and nuked and rebuilt the whole infrastructure, because that was way faster than having to dive into yet another Azure Terraform problem. It was a problem for the future. Well, the future is now.
Some background information on what we're dealing with here. We are operating a Virtual Machine Scale Set that runs a mission-critial ingress for our large-scale IT platform (we had used Azure Application Gateway before, but its limitations made us decide to rather build something on our own). In front of that Scale Set is an Azure Load Balancer, with Load Balancing rules configured for every protocol and port we have a backend service for. Updates to the list of backend services in