2018.14.2 Updated
Yesterday on the way in to work, the screen again showed an update as available. The previous version had apparently been a premature release of a developer build rather than the production release, and it was apparently pulled later that day. The new release (2018.14.2) installed overnight, so it was ready when I got in the car this morning. At first, I thought something had gone wrong again, since the release notes were the same as had been on 2018.12 (although 2018.12 had kept release notes for older versions after the announcement of remote unlocking trunks and front-trunks).
After clearing the release notes, the first thing I noticed was that the sound system sounded different. At first I assumed this was the normal intermittent issues which I had been experiencing for the past couple weeks, but it never returned to its baseline level. Fiddling with the mixer, I eventually gave-up and stopped listening to music. I did verify that the two-button salute now successfully reset the MCU.
On the way home, I had more time to fiddle with the equalizer settings. I did find a setting that sounded about right; oddly, it looked almost inverted from what I'd had with 2018.12. While I had had to bump-up the upper-mids to make-out voices before, the trebble was now overpowering (and the lowest bass, coming from the subwoofer, seemed equally clear). The mid-range was definitely still underpowered as I listened to The Battle of Los Angeles and Rage Against the Machine. Zack de la Rocha's voice was clearly audible and intelligible, whereas previously it'd been muddled. What exactly changed, I'm not sure, but it sounds as if the channels had been cleaned-up, whereas before certain frequencies were being sent to speakers that Tesla had not intended for them to reach.
For the first time, the car recognized a cyclist. Under 2018.12, cyclists, even directly in front of me, were not recognized by the car (except when there were two right next to each other). Today, it recognized a solo cyclist in front of me, displaying a car graphic in the instrument panel.