Controller should not consume 100% CPU with fork instructions

 Current Situation

A workflow W1 contains a fork instruction

Add an order at block position
[0,"fork+branch1"]
with start position
[0,"fork+branch1",0]
and end position
[0,"fork+branch1",1]
(the Join).

The order is processed and stays with the Join at the end.
Then the Controller starts to consume more than 1000% CPU. And some time later it may run out of memory.

Desired Behavior

Controller should not consume 100% of CPU or run out of memory.