Getty and Serial Getty don't seem to be initalizing properly

I have a custom device running U-Boot and Core18 that I’m working on upgrading from Core16 by tweaking the image repo. It can boot and initialize just fine, but doesn’t seem to be able to stand up Serial Getty. I flash and configure the device entirely over serial, so this is quite a problem, since I loose the ability to input into the box when this happens. After starting the Snap Daemon, the average boot looks like this:

[  OK  ] Stopped Getty on tty1.
[  OK  ] Started Getty on tty1.
[  OK  ] Stopped Serial Getty on ttymxc1.
[  OK  ] Started Serial Getty on ttymxc1.
[  OK  ] Stopped Getty on tty1.
[  OK  ] Started Getty on tty1.
[  OK  ] Stopped Serial Getty on ttymxc1.
[  OK  ] Started Serial Getty on ttymxc1.
[  OK  ] Stopped Getty on tty1.
[  OK  ] Started Getty on tty1.
[  OK  ] Stopped Serial Getty on ttymxc1.
[  OK  ] Started Serial Getty on ttymxc1.
[  OK  ] Stopped Getty on tty1.
[  OK  ] Started Getty on tty1.
[  OK  ] Stopped Serial Getty on ttymxc1.
[  OK  ] Started Serial Getty on ttymxc1.

Ad infinitum.

Anyone got any ideas? Could I be mis-configuring something that changed between 16 and 18? This image was version bumped to Core18 from Core16, so I never thought I’d see something as bizarre as serial not working. I’m using the mainline Kernel 4.14.181.

UDPATE: It seems that if I leave it for a few hours, it eventually gives up and applies my network configuration so that I can ssh in. Absolutely wack.

with all required ubuntu configs and the apparmor patchset for 4.14 ?