I hope as a soak tester I receive the update even though I am not experiencing any problems. Latest and greatest...
It's possible, if not probable, that it's just an update to the script that was used to install the update. They may have kept the rest of the update - the kernel, system, etc - exactly the same and just fixed whatever was blocking the new recovery from being installed on some phones. (That does seem to be what the problem was.)
That will save them from having to create *another* update for everybody who was on 4.4 already, go through another soak, etc. I imagine that they'll want to get everybody on system version 19.5.3 and then update everybody from there going forward. Besides the annoying home key behavior, there don't seem to be any significant 4.4 bugs at the moment that I know of, and the home key thing is more an annoyance than anything else.
But, I guess we'll see within a week or so. Somebody is bound to spill the beans on the soak test...