You should not initialize the virtual meter with defaults (checkbox). That will make the meter start with “0” and then, when the real value comes in, results in a consumption spike recorded. (Upon every gx reboot / Nodered deployment, btw.)
Thank you, I deleted the heatpump in node red and in devices of vrm. After that I added the virtual meter heatpump again with defaults disabled. But unfortunately the spike yesterday remains.