I made some humorous comments earlier (or attempts thereof)...but in all seriousness this is a very good point, which I realized after looking a bit more at what the GFS was showing. @brooklynwx99 made the same point that it's not even close to the ECMWF evolution. It's more a matter that the shortwave deepened a lot more. Plus what @CAPE mentioned about the lower heights underneath the block becoming weaker.