After much research I know it's clear that in order to use 802.3ad link aggregation on the upstream switches, the ESXi host vSwitch must be configured with a load balancing policy of "Route Based on IP Hash". The policy of "route based on the originating virtual port ID" is not to be used with link aggregation.
Also mentioned in the docs is the fact that you should not configure the "Network Failover Detection" policy for beacon probing, if you have configured the load balancing policy for "Route Based on IP Hash".
My question is - why? What is the technical reason why these requirements are in place? I have personally encountered the failure that is caused by trying to use link aggregation with the "virtual port ID" policy, but I'm trying to figure out why this policy would cause problems. Any help on this?