thats a real damn good question,why does one version work but not the other. but its not the first time people have noted a negative difference in version output.
heres some stupid questions,
was your expieriment scientific? did you use the same dvd-rw when trying both versions? did you clean it in between copies? did you then go back to 1.21 and confirm? have you tried any of your freezing discs in another player? do all of your freezes happen in the same place on each movie every time or is it random?
i have seen navigational/menu issues in newer versions as opposed to an older version,on specific titles,but not the freezeing issue. i think its safe to say that if it doesnt freeze at the same point in your pc's dvd/rom,then its a question of why your,or my,dvd standalone is having trouble reading it.
this is one of the oldest issues in this forum,and yet there is a fog hanging around it.
just out of curiosity,have you tried a dvd lens cleaner?