e.buckets[Symbol.iterator] is not a function (in UI)

Hi, I have a panel that shows the max state of any of the checks (from Nagios) in the query as shown in the screenshot grouped by hostname which works ok as if any of the values is greater than 1 I have set the threshold colors to reflect this.

But ideally what I would like is to know what check (ds:) has failed so having the check in another column. I thought I could perhaps use a filter but I get this error (e.buckets[Symbol.iterator] is not a function).

Many Thanks

Any help would be much appreciated.