Some Interfaces have the speed in and out set to 0 and the Performance Management has gaps in his graphs if the utilization is over 20 Mbps.
Release : any
Wrong interface speed configured
If interface speed is set to 0 manually or by a consequence of not providing the speed value by snmp; metric calculation will be performed but assumption is made that the speed is below 20Mbps.
Overwrite interface speed to actual value.
For sub-interface set the speed of a main interface.