I spent some time yesterday and this morning, trying to track this down.
When I was listening a couple days ago, I was listening to a playlist I had uploaded to Cloudplay, 80's Mixed Bag. I was listening to it locally, though.
So my efforts to track this down was limited to that playlist. Here's what I found...
Yesterday I was able to 100% reproduce an oddity regarding the background images in Theater view.
The first song of the playlist is by Golden Earring, the second song is by Payola$.
While watching in Theater view in the manner I described in the first message...
When the first song ends and the second song starts, the audio switched to the second song immediately. However, the background image of the first song lingers for about 5 seconds, then a blank background for a couple of seconds, then the headphones and vacuum tubes images. Also, the cover art image for the second song does not display.
I was able to see this 100% of the time, for four times in a row.
Here's the quirky part...
When I change the last letter of Payola$ from a "$" to an "s", and restarted the client PC, everything works as expected. The audio change is, as before, great. The images change at the same time the song changes, no delays or blank images, and the cover art image is displaying..
So I change the "s" back to a "$" and no longer see the odd behavior of the images anymore.
That's how far I got yesterday.
This morning I look at this again. I get the same results as the last attempt of yesterday. The images display as expected, no delays, and the cover art image displays.
Try as I might today, I can no longer reproduce any quirks.
I'm scratching my head now. Why did changing the "$" to an "s" and back again seem to fix the cause of the symptoms I was seeing?
When I originally tagged the Payola$ tunes, I cut 'n' pasted the name from a website, maybe it was an odd $ character? [shrug]
In any case, now that I have typed the $ in via the keyboard (shift-4) all seems to be OK, and Media Center is back to its usual excellent self.