ROSA Scaling the cluster (worker VMs)

We are unable to scale the `scaling` machine pool higher than 8 VMs. The reasons are unknown at the moment as I couldn't find any limit being hit on either the ROSA console or the AWS console. The initial theory was the subnet limit (16 VMs) but the AWS console shows that it has 4 IPs available. 

It requires further investigation (CPU or memory limit?) 