Activity Chart Checks : (C4133) Elements output from router that are not input

(C4133) Elements output from router that are not input

Error In:
Completeness
Description:
Textual elements (data-items, conditions, and events) that are shown flowing out of a router on an activity chart are not shown flowing in.
Example:
In the figure, data-item D is shown as an output of ROUTER_1, but is not shown flowing into ROUTER_1.
Erroneous Elements:
Textual elements