When we silenced the alert in the OpenShift cluster, after that alert was gone from the observe -> alerting tab but still could be seen in the bell icon as well as in Home -> overview tab.

4.16.7

100% 

Steps to Reproduce:   

1] Silenced any alert on the cluster that is firing. 
2] Then click on the bell icon, but that silenced alert is still there. 
3] Go to Home -> Overview alert will be still present.   

Alert can be seen in the bell icon and overview tab.

Alert should be gone from the bell icon as well as from overview tab.