Calculation Error with Group by and Nested Group by Transformation on a Counter PromQL

[krnayak2601]

• I have a counter metric of Prometheus and want to show a nested structure something like below i.e. Person1’s and his marks against it and a nested structure which shows marks per subject(refer snap1)

  Person1 | 75 |
Subject1 | 30 |
Subject2 | 45 |
Person2 | 85 |
Subject1 | 40 |
Subject2 | 45 |

Achieved it using below method

QueryA:round(sum by (Person, Subject) (increase(CounterReported[$__range])))
QueryB:round(sum by (Person) (increase(CounterReported[$__range])))
Format for both is Table

Transformation applied are:

1. Inner Join using field Person
2. Organize fields by name
   Disabled Time1 and Time2
3. Group by
   1.Person:Groupby
   2.Subject:Groupby
   3.ValueA:Calculate Last
   4.ValueB:Calculate Last
4. Nested Group by
   Person:Groupby
   Subject:Ignored
   ValueA: Ignored
   ValueB:Groupby

Now coming to my issue when I open the dashboard it shows me above marks as expected and an immediate refresh on dashboard turns value to 0 for all the marks.

Same thing happens when I change time range i.e. if time is change to 5 hours it shows correct values and an immediate refresh button updates the values to 0.

Grafana version is 11.x

An immediate refresh return all values to 0