'Empty' timeslot in NIC data - why?

[mcv]

Today we see an 'empty' timeslot on all our hosts from 8:42 AM to 8:56 AM. Our network guys says that everything was running smoothly at that time, so what could cause this?

[thomas_henmar3]

I experienced a Dynatrace Maintenance Screen at that timeframe. I can see that multiple tenants @EU cluster has the same gaps.