So, in addition to a completely missed call in the morning, it looks like I had a couple more throughout the day as well. If it wasn't for voicemail being left and me getting a voicemail alert, I wouldn't have even known (since no missed call indicator even appears).
I can only imagine that there could be even more missed calls that didn't result in a voicemail, of which I basically would have no knowledge off.
The strange thing is that the voicemail indicator as well as text messages, email, and other notifications are coming through just fine, even around the same exact time, or at least shortly before and/or after, the non-delivered calls are being made, so it doesn't seem like there's any type of connectivity issue.
Something does seem off, more than just some sort of an occasional weirdness.