Group by returning different value than expected

[pvdb]

Hey folks.

why would…

group by (env) (rate(some_metric{env=~$env}[1m]))

return ‘1’

when

rate(some_metric{env=~$env})

returns ‘0’

Note that

group by (env) (-rate(some_metric{env=~$env}[1m]))

also returns ‘1’