Export (CSV, All Fields) and Export (CSV, Current Fields) Issue link value shows in multiple column

NOTE: This bug report is for JIRA Server. Using JIRA Cloud? See the corresponding bug report.

Summary

In the exported Excel sheet of a search filter, Issue Link Fields with multiple links shows in multiple column with the heading Outward issue link (Blocks), Outward issue link (Cloners), Outward issue link (Duplicate) and Outward issue link (Relates)

How to Replicate

1. Go to Search Filter
2. Filter Projects which contains multiple Link Issues
3. Export (CSV, All Fields) or (Export (CSV, Current Fields)
4. Link Issue Column shows multiple

Expected Result:

Value on the heading for Link shows the name same as UI in a single column

eg. Link issues with single column

Actual Result:

Value on the heading for Link Issues fields shows in multiple columns:

Eg. Outward issue link (Blocks) | Outward issue link (Cloners) | Outward issue link (Duplicate) | Outward issue link (Relates)

And repeated Columns if there are multiple value in the same column:
Eg. Outward issue link (Blocks) | Outward issue link (Cloners) | Outward issue link (Duplicate) | Outward issue link (Relates) | Outward issue link (Relates) | Outward issue link (Relates)