So I'm double-posting to let you all know of a new development: The issue only happens after my system wakes from sleep or hibernation. Restarting the computer resolves the issue temporarily, but the issue returns the moment it goes back to sleep/hibernation and wakes back up.
For now I've disabled sleep and hibernation on my system and just leave it on unless I'm leaving the house or going to bed, but this is not an ideal long-term solution given the cost of electricity in Hawaii and the way I use my system.
Further help in isolating the cause of this issue would be greatly appreciated, but it's not quite as urgent as before.