Problem: The flow editor does not prevent you from adding connections that wire the execution path of a flow back onto itself (at an earlier point in the flow's execution path). This situation may not cause errors when you generate runtime code. However it is very likely to lead to errors during runtime processing.
Workaround: When you want part of a flow to be iterated multiple times so long as a certain condition is true, use a While node (see the topic "Creating a loop" in the Enterprise Service Tools documentation).