This is a clear example of the port-channel load-balancing algorithm not being suited to the traffic flows passing over the link.
Take a look as this document to better understand your options
...keep in mind different platforms will have different load-balancing algorithms available. Consult the relevant configuration guide.
Agreed with other post, it all depends on how you testing also. if the traffic real is what it showing there based on LB method you use
post the configuration to suggest better.
How many links do you have in the PC - it is best to have a even number and than an odd one due to load balancing ratios.
what is the PC connected to?
Having a load balancing method on one side of the pc doesn't necessarily mean you use the same on the other end