Thanks for the question,
Right now no down ports for each incident
About vmnic's too ... what is very strange that's the issue (3 times right now) appears on one ESXi (and only one at a time) and crash network communication on 15, 20 vm (vm with e1000, vmxnet3, vmxnet2) each time.
You mentioned that if you migrate the VMs to another host that this fixes the issue. What happens when you immediately migrate the guest back to the original host? Does the failure remain?