Symptom:
The issue occurs when using the Linked Filters feature on dashboards. When a user starts by selecting a filter value for a parent filter and proceeds to select a value for a child filter, Looker incorrectly removes the value selected for the parent filter.
Current status:
We're actively working on a fix and we will deploy it to Looker hosted instances as soon as it's available. We will also update this article as soon as the status is changed.