QOS strange impossible high bandwidth

I had QOS running for a while, but I have trouble to make sense of the graph for RED.
I set the uplink at a max limit of 5Mbit/s, but I get these extremely high spikes in class 110 which is uplink every now and then.
Doesnt make sense.

Something doesnt seem to work.

Maybe I missinterpret something, but it looks odd.
How can I have a 4Gbyte/s transmission from class 110 when the network card is 1Gbit and the maximum has been set to 5000kbit/s ?
To me it is a contradiction. So what do I interpret wrong ?

you can’t. To me it looks like a fluke. Not knowing how the QoS is implemented (what I know is that it is really complex) I cannot make any hypothesis, but my base case would just that, a very brief fluke of the gauging system.

If it is a fluke or not, that would scare the heck out of anyone.
How do I know it doesnt really happen. 4GB/s upload is severe !
No-one knows what burst capability is built into interfaces for nefarious reasons.

Otherwise if it is a bug, it would be nice if it is acknowledged it is a bug so the graph can be interpreted correctly.