Wrong interface name on SNMP sensor

I've configured SNMP v3 on a Cisco 6880-X-LE switch and discovered it with PRTG. Works fine, but it does not show the interface names as expected. I've changed the Port Name Template for the particular group to "[ifalias] [ifname] [ifsensor]", since I otherwise end up with a bunch of sensors with the same name. I was expecting it to show me something like this:

accesswitch01 te1/5/9 Traffic
accesswitch01 te2/5/9 Traffic
accesswitch01 Po23 Traffic

But it show this:

accesswitch01-01/1 Traffic
accesswitch01-01/2 Traffic
accesswitch01 Po23 Traffic

According to the manual [ifname] is "The textual name of the monitored interface as assigned by the local device", but it's the same name for every port channel member on the switch ("-01/1" and "-01/2").

Is it possible to get the physical interface name in the sensor?

physical-interface sensor snmp snmpv3