Network Graph Sum of several machines, glitches in the timestamps

Hello, i´ve configured an Network graph for the network thoroughput of 6 machines (Transform -> Add field from calculation, Calculation “Total”). But when you look at the graph you see glitches, i´ve found out they are in die Query as you see the second screenshot. When i look at these date for each machine these glitches are missing. I have no clue where the issue is. Do anybody have a hint for me ?

Grafana reads the data from an influxes every minute. Telegraf is asking the devices an every minute via snap an writes it to the database.

Kind regards.