When we use parallel flow in flow designer it keeps on waiting even though one of the flow logic completes its execution
End action was not defined in the flow logic
Verified the flow designer which was configured on the table and observed that End actions were not defined to the flow logics.
Since there was no End action defined to the flow logic it keeps on waiting for other parallel flow logics to finish its execution.
Adding the End actions to the flow logic in the flow designer will resolve this issue.
Please browse the below document URL to know more about the flow logic in flow designer.