Tooltips picks up wrong query when using InfluxDB with a group by() clause

[Franz1983]

Hello, in a particular case the value and the name displayed in the graph Tooltips are wrong, with this i mean that data are picked up from a completely different query (instead to be picked up by the query defined in the rule). Tests have been done with Grafana 6.7.4 and InfluxDB 1.8. To reproduce the issue create an influx query like this one in the screenshot:

If the query contains a group by() clause ( i'm using the group by on a a tag key in order to use the Grafana macro $tag_myFielKey, so that the query name will be automatically composed), values and label in the graph tooltip are picked up from a different query. The issue happens if the lenght of the field key (in this case a string) over which the group by is done is longer than 20 characters. I've done a test with a field's lenght of 25 and the problem appears again.

Regards Francesco