As the title suggests, after updating to 10.13.2 today, my dock turned white and was no longer semi-transparent. I restarted a few times, and that did not fixed the issue. After digging around, I looked in system prefs > accessibility > display, and reduce transparency was newly checked. I unchecked it, as this was something I didn't enable. Out of curiosity, I restarted the computer again, and reduce transparency was enabled AGAIN. Once more, I unchecked it and restarted. And yet again, reduce transparency was enabled. What is going on here?