Update... Solved!

Again I got the entry:
2017-09-14 08:40:22.230 MySensors: Gateway Version: 2.1.1
2017-09-14 08:40:24.215 MySensors: Gateway Ready...
in the log.

I found that I had a broken sensor. When checking the sketch for this sensor
i noticed that I had enabled repeater function. After removing this faulty sensor, there are no more
spamming in the Domoticz log file.

Hi

Yesterday I noticed that the log was "normal again". I can not tell if it has to do with the addition of power supply or changing the usb cable or something else. Thank you guys for all help.

/John