When attempting a bulk migration it fails during the subtask of "relocate on source side".
app.log in HCX manager will show entries similar to:
Log analysis identified this to show: "source side relocate failed for the virtual machine. error is currently connected network interface 'Network adapter 1' uses network 'DVSwitch: <dv switch ID>, which is not accessible."
vpxd.log in vCenter will show entries similar to:
a failure when Checking for DVS with portgroup key dvportgroup-###, port key
VMware HCX
VMware vCenter
This is caused by a stale vCenter DB entry.
Migrate the virtual machine over a different service mesh(one uses a different virtual Distributed switch(vDs)/network container. Then reverse migrate the virtual machine using the impacted service mesh/network container. This will force vCenter to update the database with a new port entry.