Marking task completed generates description edit event

Summary

Marking task completed generates second event: @XXXXX changed the description. Also, edited N minutues ago by @XXXXX added to the bottom of the description.

Steps to reproduce

1. Create an issue with task list.
2. Mark first task as fixed **without editing description"
3. See the edited just now by @XXXXX under description and extra event @XXXXX changed the description less than a minute ago in addition to the marked something completed.

Example Project

Example issue on Gitlab.com - https://gitlab.com/sashk/test/issues/15

What is the current bug behavior?

Two extra events shown.

What is the expected correct behavior?

1. Only messages should show up is @XXXXX marked the task ZZZZZ as completed N minutes ago

Relevant logs and/or screenshots