Fractional traffic weights don't seem to be set accurately

[herojan]

I have created a stackset called ss-stack with stacks v1 and v2. When I switch traffic using fractional values, the resulting traffic percentage is slightly inaccurate. See the following examples:

Examples

zkubectl traffic ss-stack ss-stack-v2 50.1
Name       │Actual│Desired
ss-stack-v1    100      50
ss-stack-v2      0    50.1
Name       │Actual│Desired
ss-stack-v1   50.0    50.0
ss-stack-v2   50.0    50.0

And in the stackset status I see:

[
  {
    "serviceName": "ss-stack-v1",
    "servicePort": 5678,
    "stackName": "ss-stack-v1",
    "weight": 49.95004995004995
  },
  {
    "serviceName": "ss-stack-v2",
    "servicePort": 5678,
    "stackName": "ss-stack-v2",
    "weight": 50.049950049950056
  }
]

Another example is

zkubectl traffic ss-stack ss-stack-v2 50.8
Name       │Actual│Desired
ss-stack-v1   50.0      49
ss-stack-v2   50.0    50.8
Name       │Actual│Desired
ss-stack-v1   49.1    49.1
ss-stack-v2   50.9    50.9

And the stackset status is

[
  {
    "serviceName": "ss-stack-v1",
    "servicePort": 5678,
    "stackName": "ss-stack-v1",
    "weight": 49.09819639278557
  },
  {
    "serviceName": "ss-stack-v2",
    "servicePort": 5678,
    "stackName": "ss-stack-v2",
    "weight": 50.901803607214426
  }
]

The stackset used was:

apiVersion: zalando.org/v1
kind: StackSet
metadata:
  labels:
    application: ss-stack
  name: ss-stack
spec:
  externalIngress:
    backendPort: 5678
  stackTemplate:
    spec:
      replicas: 1
      version: v1
      podTemplate:
        spec:
          containers:
            - name: gw-test-app
              image: hashicorp/http-echo
              args: ["-text", "Stack V1"]
              ports:
                - containerPort: 5678
              resources:
                requests:
                  cpu: 1
                  memory: 100Mi
                limits:
                  memory: 100Mi

It was applied and then reapplied with v1 replaced by v2.