Kubernetes (minikube) pod OOMKilled with apparently plenty of memory left in node

I'm using minikube, starting it with

minikube start --memory 8192

For 8Gb of RAM for the node. I'm allocating pods with the resource constraints

    resources:
      limits:
        memory: 256Mi
      requests:
        memory: 256Mi

So 256Mb of RAM for each node which would give me, I would assume, 32 pods until 8Gb memory limit has been reached but the problem is that whenever I reach the 8th pod to be deployed, the 9th will never run because it's constantly OOMKilled.

For context, each pod is a Java application with a frolvlad/alpine-oraclejdk8:slim Docker container ran with -Xmx512m -Xms128m (even if JVM was indeed using the full 512Mb instead of 256Mb I would still be far from the 16 pod limit to hit the 8Gb cap).

What am I missing here? Why are pods being OOMKilled with apparently so much free allocatable memory left?

Thanks in advance