Note: Not a solution but marked as such to elevate a key reply
Hi all.
I’ve luckily found a native workaround for recurring tasks to trigger rules when completed. 
What worked for me:
- A rule that complete the task when it’s due.
- Any rule where the trigger is the Task added to the project.
For example:
3) The result
Before: completing a task with the normal button (rule is not triggered by the recurring task):
After: completing the task using the rule (rule is triggered)
Remark:
You probably also need this option to be activated on the second rule.
Hope that helps 
Arthur