Long running workflow appears stuck, no logs (calling subflows in sync mode)

[bvandewe]

What happened:

A "parent" workflow appears stuck while executing a foreach state that calls a subFlowRef. The first two instances of the "child" flows completed successfully (got Workflow executed and Application is shutting down... in the workers' logs) but then no other instances were started and the parent flow appears stuck, nothing happens in the logs, no error/warning message at all.

Parent/Caller flow

...
"states": [
...
{
      "name": "Reset Widgets",
      "type": "foreach",
      "inputCollection": ".forms",
      "actions": [
        {
          "name": "Create or Reset form widgets",
          "subFlowRef": {
            "invoke": "sync",
            "workflowId": "form-indicators-reset",
            "version": "latest"
          }
        }
      ],
      "iterationParam": "form",
      "end": true
    }

What you expected to happen:

With the input data, i expected 50x subflow instances to be created... Only two were started and executed successfully.

How to reproduce it:

Try running a workflow that iteratively calls a subflow for more than 2 expected subflow instances...

Anything else we need to know?:

Will try in async mode and revert asap.

Environment:

Latest release ( 0.3.15), K8s v1.22.3