Increase() action and show in grafana

Hello
could anyone response to my question?

The type my_nodes_add_total is a counter.
I know that increment() only checks the first data point and increments it.
In the bellows graph, this count increments the value 1, but I don’t understand why the return value is 2.

sum by(reason) (increase(my_nodes_added_total[1m]))


sum by(reason) (my_nodes_added_total[1m])

When the query option changes the time period from the last 5 minutes to the last 7 days, Grafana shows a value of 0.

sum by(reason) (increase(my_nodes_added_total[1m]))