Graphs of traffic in vs out don't match

I am performing a large data transfer, with data coming into the switch (CRS328) on bonded pair ether 17 + 18, and out ether1. I started a graph of those interfaces and they SHOULD match, but they don’t. The ether1 graph looks right with data being sent at around 600Mbps. But the ether_17_18 graph SHOULD should data being received at the same rate. (I enabled ether_17_18 graphic only the last hour).

Why don’t they match? Does graphing not work on bonded pairs (802.3ad)?
graphs.jpg