ET340 not showing all 3 phases, I only see phase 2 and 3 in gui

Hello community,

since some weeks, I can see that the ET340 meter only shows phase 2 and 3 in the Venus os, I use it to measurement the pv output in the gui of venusos, I have a raspberry pi with a waveshare USB-RS485-Konverter to read the data, it was working for like 1 or 2 years, has someone the same problem or know what can be the problem?
i am on the latest Venusos firmware 3.42, is it possible that it is a firmware bug?
when I plug in the USB-RS485-Konverter to the notebook and open the app from carlo gavazzi, I can see also phase 1, it looks like it is not the power meter and also not the connection with the rs485 cable.

kind regards,
martin