I’ve been testing and tweaking my designs and I noticed something weird about the Watchface Shuffle feature.
When I turn on Watchface Shuffle (which I love - thank you for this feature!), my 1200 
bpm and Beyond the Sea watch faces revert to previous versions - ones with plain black Dim backgrounds. Re-syncing those watch faces updates them to their newer monochromatic Dim backgrounds.
As my watch continues on shuffle, my Iridescent watch face also reverts to a previous version - one with a rotated Dim center point. Re-syncing that watch face updates to the most up-to-date Dim center point.
You get the idea. Even if more recent versions of a watch face have been synced to the watch more recently, Watchface Shuffle uses older (cached?) versions and reverts all updates.