Moxy Monitor

I use a Moxy monitor on a Edge 1040, Iq data field 1st Sensor, ANT+ signal. I experience zero values in the Moxy data and I have the impression that this happens whilst doing a workout with intervals and the drop out happens like the appr. first 2 minutes from the beginning of every second interval. This might be a coincidence but it seemed to me like a pattern in my last training. Does anybody have an idea how to fix or a similar experience?