1. Go to Administration >> System >> General Configuration >> Edit Configuration >> Comment visibility >> Groups & Project Roles.
2. Go to an Issue >> More Actions >> Attach Screenshot >> Comment Viewable
3. In the group list, I saw the following class:

Groups
    com.atlassian.crowd.impl.ImmutableGroup@42b66b45
    com.atlassian.crowd.impl.ImmutableGroup@9099db68
    com.atlassian.crowd.impl.ImmutableGroup@976d6f29

By default, the group list should be like this:

Groups
    jira-administrators
    jira-developers
    jira-users

I test on JIRA 4.4.4 and the issue does not occur there.