I am not an expert with link aggregation, maybe nobody here is.
It seems there is aggregated eth0 with eth2, and eth1 with eth3.
The only unusual setting is the
BOOTPROTO=static for eth0.
You have set
xmit_hash_policy=1.
Maybe you should change to
xmit_hash_policy=layer3+4, then two hosts can use more interfaces if more services (ports) are involved. But the other way is controlled by the LAN switch.
And - maybe everything works as designed, according to
this article.