It's not a bug, just the game moving fixtures to fit them in any way it can. There are a couple of limitations to its algorithim, which is why it doesn't always do a great job. The worst I've had, ever, is four league games inside 8 days.
If BSkyB had its way Im sure the top teams would be playing 3 games in 3 days over the festive season and maximise their income.
Seriously though I do think this is one aspect of the game which has got worse over the years I never recall this cropping up in earlier versions or indeed in football management games of my youth. I could be wearing rose tinted glasses mind, but really this is one bug while not game breaking that needs fixing ASAP, although not sure why the OP had to create 2 threads for the same issue
There was a bug in the old patch where some guys were getting important international fixtures the same day as having league matches, so they lost all their key players.
The December month is the challenge for EPL teams, thats what Wayne Rooney have been complaining about in real life
it is very rare that a professional football team is expected to play two matches on consecutive days, especially during the Christmas period when there is still 5 months of the season in which to play a re-arranged match..