Hi,
today at 5am, both IPFIX-sensors of our monitoring system (PRTG), stopped showing data.
We figured out, that the timestamps, transmitted from the routers, were wrong (offset was around 16 hours).
After a reboot of both router, both sensors showed the data again - the timestamps were correctly transmitted again.
The clocks (top right in the Winbox) on both routers were always correct. Why lost NetFlow/IPFIX its time? Especiall on both routers at the same time...
Both router are set to a public NTP-service.