Issue links in a Bug are getting deleted which are created from a Test Run defect, when we have multiple Test Runs for a Test

Description: Tests under the issue links are getting deleted which are created from a defect if we have multiple Test runs for a Test

Pre-conditions: 1 Test, 1 bug, and 2 Test Runs

How to reproduce

1. Create a Test
2. Execute the Test with two executions.
3. Add the same Defect (Bug) in two Test Runs.
4. Delete the Defect from one Test Run 
5. Then in the Bug, related Test and Test Run are getting deleted from the issue linking.

Actual result/Attachments: The Test and Test Run are getting deleted from the issue linking in the Bug even if the same bug is linked with the other Test Run.

Expected result: If we delete the Bug from one Test Run, only the particular Test Run should be deleted from the Bug but not the related Test from the issue linking in the Bug. Because the same bug is linked with other Test Run in the same Test.