Activity Tags not visible

Hi

Activity, Tags not visible in my Gitlab instance which is on 8.8.
Recently I upgraded it form 8.0 to 8.8, earlier also (in 8.0) I had this issue which used to occur once in a month.
I used to kill sidekiq process and restart gitlab the activity used to show up. After upgrading to 8.8 the problem has worsened now it occurring daily.

I have found some documentation regarding sidekiq troubleshooting this issue in Gitlab.com but details steps are not mentioned. if any one has faced a simillar issue, any guidance will be helpful.

Thank you !