Solved! Go to Solution.
Just received a reply from my bug report:
"our colleagues have had a look at this, and it seems that this has now been fixed. Please do check for any pending updates on your phone to get this sorted. To do this head into the device Settings> Software update> Download and install."
So it looks like it's a known problem and has been fixed, but I have no pending updates on my end yet. Maybe it'll get rolled into an upcoming update? I guess we'll see...
Wishing, though, that clearing cache partition were as easy as clearing the cache of an app.