Live Feed users with 'admin' and 'invited' state in Live Group Profile are unable to query and visualize hashtags. If the state of a user's live_group_member profile is 'admin' or 'invited', when they attempt to query the group's private messages by hashtag on live feed, they get missing results.
After carefully considering the severity and frequency of the issue, and the cost and risk of attempting a fix, it has been decided to not address this issue in any current or near future releases. We do not make these decisions lightly, and we apologize for any inconvenience.
As a workaround, go to the live_group_member record and change System Administrator from 'admin' to 'active'. This will correct the behaviour.