When I have the process with several sources (Throw Link Event) and single target (Catch Link Event) I am getting error during validation and building :

There should be at least 2 link events to make a connection

But when I have several targets (Catch Link Events) and single source (Throw Link Events) process pass validation, can be built and executed .

According to the BPMN 2 specification, this behavior should be reverted. It is allowed to have several Sources with same Link name but Target should be only one for the Link name.

Paired Link Events can also be used as “Off-Page Connectors” for printing a Process across multiple pages. They can also be used as generic “Go To” objects within the Process level. There can be multiple sourceLink Events, but there can only be one targetLink Event. When used to “catch” from the sourceLink, the Event marker will be unfilled. When used to “throw” to the targetLink, the Event marker will be filled.

Page 262 of the BPMN 2.0 Specification

h4.  Acceptance Criteria

1. It should be possible to execute process with several Sources (Throw Link Event) with same Link Name.
2. It should be possible to use only one Target (Catch Link Event) for the Link Event for the same Link Name across the sub-process level.