Network not loading at boot

[caver01]

Pi3
Adafruit 5.25v
RetroPie Version 4.01
Built From: 4.0 RetroPie image
USB Devices connected:
iPAC4, TurboTwist2, UTrak, usb hub (AC powered)
Controller used: IPAC

Hey, guys, this is more of a Raspbian question I think. Would anyone know why my system no longer boots with ethernet networking turned on? I can drop out of ES and issue a sudo dhclient eth0 and it fires right up, but at boot, I don't get networking, no IP address (this is hardwired to the built-in ethernet, not WIFI).

The strange thing is that sometimes it does work. I can't explain why. Sometimes I boot the system and it has a network. Sometimes it does not. Usually not.

This seems like a timing thing, but I don't really know where to look. I would be happy with a brute force fix, if someone said, "look, just put that command into a startup file here. . ." or something, that would be fine. Root cause would be nice to know, but I am fine with just a fix. Ideas?

I should add that it has been going on for a while I think, probably since I build the setup from the 4.0 image. I just never really made a big deal about it.