P: Color problems with slideshows in Lightroom 5

The Problem:

A client uses a MacBook Pro, an Epson 77c projector, and Lightroom to show slideshows using the slideshow module of Lightroom. In Lightroom 5.0, the reds and oranges of the slides when shown on the projector are over-saturated - but *only* when using the Slideshow module. This is a new problem since upgrading to Lightroom 5.0.

Additional details:

* I have created a calibrated display profile for the projector (using a Spyder 4 Elite) and made sure that the Mac is set to use the proper calibration for the projector in the Displays pane of System Preferences.

* Even if I select a different (incorrect) calibration for the projector, such as the generic sRGB one provided by Mac OS X, the problem persists (although of course the colors in the photos look worse in general, too).

* As I said, this is a new problem with Lightroom 5. With the exact same setup and photos in Lightroom 4, I do not see the problem.

* The oversaturation only happens with the slideshow module displayed on the projector. It does not happen if the very same photos are displayed on the projector using loupe mode or Lightroom 5's new fullscreen mode in the Library module.

* The problem only happens with the projector. If I display the very same photos using slideshow on the MacBook Pro's built-in screen, the photos look fine. I hooked the MacBook Pro up to an external monitor (a Dell UltraSharp U2412M), configured things to be exactly the same as they were when I used the projector, and did not see the problem.

* The photo files in question are RAW photos from a Nikon D7000 and/or D90 (saw it with photos from both cameras).

* I tried several slideshow presets - including the built-in ones - and saw the same behavior with all of them.

* Typically the MacBook Pro is setup to mirror the display to the projector (so, the same thing appears on both screens). I did try setting up the projector as a second screen and used Lightroom's second window feature to run the slideshow on the projector, with the same result.

* The MacBook Pro is running Mac OS X 10.7.5.