Query do not return enough results with filter of "group by , having"

we have a query like below, created_at is the time column
```
SELECT transaction_id, count(*) as cnt FROM point_transaction where created_at >=1616760000 and created_at < 1616846400 group by transaction_id having cnt > 1 limit 400
```
It is returning random results, sometimes 38 items, sometimes 20 items. In our dataset it should have much more than 400.

Reproduce the supplied SQL query against Pinot using the stated time range and dataset, then trace the group-by, having, and limit query path to identify why results vary and stop below the limit. Done means repeated executions return stable results and include all qualifying groups, up to 400.

Written by the indexing model from the issue text.