Adding a related issue by keyboard adds the issue twice

Tried this on staging:

/cc: @MadLittleMods, @jschatz1

I can reproduce on https://staging.gitlab.com/ and latest EE master, 8bd15968

But this was was not occurring a couple days ago (bc97513a random master commit I was on) and I haven't touched it since then.

I'll try a git bisect to see where it broke.

Caused by https://gitlab.com/gitlab-org/gitlab-ee/commit/932b94f911394543a0377d712b2b28da827e4aad#5c81a39dd0a93216b1a0f2dcc14fa6ef4da373eb_33_33 in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/12720

I'll work on a fix

assigned to @MadLittleMods

added bug label

mentioned in merge request !2420 (merged)

Fix is here https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2420. I'll add some tests

mentioned in commit 91b17b06

closed via merge request !2420 (merged)

mentioned in commit 7555289f

mentioned in commit ccfc9817