Why are all interfaces not used in bonding Mode 2 or Mode 4?

Issue

• Why all interfaces are not used in bonding mode=2 or mode=4 and uses only one interface?
• In bonding mode 4 (802.3ad LACP) only specific NIC is used for receive (rx) and transmit (tx) and the rest of the NICs are not used:

eth0 - RX bytes:   58970058 (56.2 MiB)  TX bytes:20342326161 (18.9 GiB)    <-- most TX
eth1 - RX bytes:49296441110 (45.9 GiB)  TX bytes:    1872543 (1.7 MiB)    <-- most RX
eth2 - RX bytes:   66462573 (63.3 MiB)  TX bytes:    2495475 (2.3 MiB)
eth3 - RX bytes:   39914810 (38.0 MiB)  TX bytes:    4014612 (3.8 MiB)

• Most traffic on Bonding Mode 2 is passed via one interface ethX and nearly nothing is passed via another interfaces. It is expected that both interfaces should be used so as to have more throughput.
• Why does the outgoing network traffic only go to a specific interface in Red Hat Enterprise Linux when using bonding?
• Traffic doesn't balance correctly across multiple interfaces when using load balancing bonding modes like 802.3ad LACP.
• Why Link Aggregation bonding mode doesn't utilitze bandwidth of multiple NIC
• I have configured 4x 1Gbps interfaces in a bond, why do I not get 4Gbps in iperf and other bandwidth tests?
• Bonding performance is not as expected, it goes at the speed of a single interface, not at the speed of multiple interfaces