Personally all I know is that until about 01:00 whereas I used to get problems I don't now. However my wife who is well asleep by that time but who often awakes around 04:00 and goes downstairs and watches VM, says she is now getting identical freeze problems until around 05:00
This is the weekly TV schedule updating itself. For me its off & on between midnight and about 3 am. I've just moved to TIVO to see if that stops the issue as I'm a bit of nighthawk so it caused me no end of grief.