Understanding ESXi host connections...

[wintermute000]

MLAG probably doesn't have much to do with it, since it appears as a normal port channel to the downstream host - however a scripted install probably doesn't start with a dvswitch (not sure, haven't looked into this particular aspect) - so no LACP. You might be stuck with 'on'.

I'd start with getting their script and analysing what exactly they're setting up vswitch wise, then go from there. If they're matching a switch etherchannel ON with a standard active/passive pairing of vmnics for mgt then that's your problem right there.

https://pubs.vmware.com/vsphere-60/index.jsp?topic=%2Fcom.vmware.vsphere.networking.doc%2FGUID-D34B1ADD-B8A7-43CD-AA7E-2832A0F7EE76.html

Incidentally, I'm not terribly sure what the benefits of scripted install are over autodeploy aside from reliance on the autodeploy TFTP, but if you're deploying so many ESXis so often that you need an autodeploy solution you'd think that you'd want to get away from local installs entirely (also ease of patching... reboot and boom boot of new image/patches).