My 5 month old started doing this too in the last two weeks! Nothing changed, I never rearranged any furniture or anything.
However, I did notice that he does this more often when his litter box needs to be cleaned (I use UGODOG), so maybe they are just clean freaks!?
He was getting to be really good at using his UGODOG and almost had no accidents anymore. Now he often decides that getting his front paws on the litter box is good enough....