I guess I spoke a bit too soon.
In my boot volume, my MBP's battery has consistently been read correctly since I updated to 10.14.6, but I just booted into another volume with around 13 hours showing as remaining, and now that I've booted back,
after only 5 (five) minutes, it shows
only 5 (five) hours remaining.
Historically, I know the number will slowly increase to what it should be, but it's really annoying to see that the problem persists.
More: Remaining charge % is being read correctly, but it's not being translated to remaining time correctly.
After about 1 1/4 hours, remaining time is up to 10 1/2 hours.