Summary

JIRA description & comment fields adds extra hyphens (dashes) to closed issues mentioned/linked into it upon description / comment update and save.
Each update will add a couple of hyphens, one at left and one at right hand side of the issue in the closed or done statuses.
Seems like a problem related to fact the issue is strikethrough since it is closed.
Happens only with issues not with normal strikethrough text.

Steps to Reproduce

1. Create issue which has link to closed issue in the description.
2. Edit this issue description several times using the Visual (not Text) editor
3. Two dashes are added to the link to the closed issue each time the issue's description is edited

Expected Results

The issue link should display strikethrough with not hyphens (dashes) beside it.

Actual Results

The issue link displayed strikethrough with extra hyphens (dashes) beside it corresponding to the number of edits.
Please check the screenshots.

Workaround

Use the Text editor when linking issues and avoid editing into the Visual view.