Query Analytics Dashboard: Slow appearance of query time distribution graph for some queries

Steps to reproduce:

1. Navigate to QAN and filter some results for MySQL;
2. Click on some query to see details;
3. Verify Query time distribution graph present;

Actual result:

Query time distribution absent. (Seems like it needs some time to be shown). After several minutes if I can see details for the same query graph is already present. The same while navigating to other page and changing filters.

Expected result:

Query time distribution graph present.