Upgraded to Grafana 8.5, now alerts from InfluxDB always show "no data" despite thresholds work - grafana

Question

I upgraded to Grafana 8.5 and now the alert rules that previously worked have stopped working.
This is my query:
SELECT mean("temperature") FROM "mymeasurement" WHERE $timeFilter GROUP BY time($__interval) fill(linear) tz('UTC')
This is plotted correctly:
Now I set up an alert:
When I test it, I get:
{
"firing": false,
"state": "no_data",
"conditionEvals": "false = false",
"timeMs": "9.499ms",
"logs": [
{
"message": "Condition[0]: Query",
"data": {
"from": 1652276950339,
"queries": [
{
"refId": "A",
"model": {
"datasource": {
"type": "influxdb",
"uid": "ZwglYwS7k"
},
"groupBy": [
{
"params": [
"$__interval"
],
"type": "time"
},
{
"params": [
"linear"
],
"type": "fill"
}
],
"measurement": "mymeasurement",
"orderByTime": "ASC",
"policy": "default",
"query": "SELECT mean(\"temperature\") FROM \"mymeasurement\" WHERE $timeFilter GROUP BY time($__interval) fill(linear) tz('UTC')",
"rawQuery": true,
"refId": "A",
"resultFormat": "time_series",
"select": [
[
{
"params": [
"temperature"
],
"type": "field"
},
{
"params": [],
"type": "mean"
}
]
],
"tags": [],
"tz": "UTC"
},
"datasource": {
"id": 4,
"name": "my-datasource"
},
"maxDataPoints": 1500,
"intervalMs": 200
}
],
"to": 1652277250339
}
},
{
"message": "Condition[0]: Query Result",
"data": {
"fromDataframe": true,
"series": []
}
},
{
"message": "Condition: Eval: false, Query Returned No Series (reduced to null/no value)",
"data": null
}
]
}
What has changed in 8.5 that this doesn't work any more? The exact same query works fine in 7.5