I don't see how that is possible, let me explain what creating a blank tg3.conf does:
-with Unraid v6.10.2, and only with that release, if VT-d is enabled and there is a NIC that used the tg3 driver that driver won't be loaded Unraid unless a blank tg3.conf file exists.
-with any other Unraid release, including v6.10.3 that code doesn't exist, i.e., it won't make any difference having that file or not, even if you have a NIC that uses that driver.
If your NIC isn't loading with VT-d enable it's a different problem, please post diags after booting witn VT-d enabled and VT-d disabled.