Explanation is correct but problem still occurs
For now I've apply workaround with Parallel Action. It's nasty (25 branches) but it works...
I'm curious how big WF can be? Now I've almost 500kB. I can't split main WF into subWFs cos I'll be forced to pass a lots of parameters (+ item context) from main WF into subWFs.
Well, it is said that workflow in O365 should not have more than 100 actions.
On the other hand - what is your design, that you cannot have the checkbox to wait checked? Why do you need to move forward once tasks are assigned?
My case is to send a task to Approver and Deputy (Deputy - person who can approve task instead of Approver) for a specific group of brands. Approver and Deputy are persons (not group).
I must collect and aggregate all SKUs by brand and send one email (one task) to Approver and Deputy.
So I'm collecting all rows (repeating section), aggregate them by Brand, and create a Task for each brand.
It is important that task can be approved/rejected only by Approver or Deputy so I must create one approval task for both (first response wins).