I've noticed this trend with a number of major-label 5.1 releases (aside from Steven Wilson's stuff, where he apparently has enough clout to insist on no mastering of his mixes) of the last 5 years or so, they seem to be getting brighter and brighter as the years go on. This one is just the latest, and maybe most extreme example, but APP's Ammonia Avenue (and to an extent Eye in the Sky) suffers from it to, as do all the titles that Craig Anderson mastered for WMG, including the Fleetwood Mac 5.1s and especially the Doobie Bros. Quadio which it literally pains me to say is so bright it's pretty much unlistenable for me.
I'm not sure if the cause of this is aging mastering engineers who've lost the top end of their hearing and are compensating with EQ as a result of what they're hearing, or if they can hear fine and they're mastering with a listener lacking in top-end hearing in mind, but it seems entirely unnecessary either way. Giving the high end of the EQ spectrum a little bump in mastering can really make a vintage recording come alive, but what's going on with these is several levels of magnitude beyond that.