Logging Work Done doesn't show work done comments.

We are currently doing our user Acceptance testing for new projects we are placing into our JIRA installation. We are finding that When "logging work done" in an issue, the time estimate updates, but the comments are lost. Work done comments are not captured and the work logged summary shows <no comment>

The users have access to Log work done and permission to add comments is also granted.

Any advice you can give is appreciated.

thank.s.