@MarcLasserre_GCS I tried using Declare Trigger rule, but it seems that the child property (pyStatusWork) is not committed yet when it triggers.
On pyStatusWork change we need to call a data page which count how many children are in each status to determine a custom property value on the parent case. The report executed by the data page extracts the old value of pyStatusWork even though I can see in the tracer that the child case has already changed status.
We also tried using a Declare On Change rule or adding ad Update Case smart shape in the child case flow where we change the status, but we got the same result.
Also already tried putting the property-set in a pre-processing action of the flow action following the assignment which change pyStatusWork.