Hello here.
I've set the monthly calendar to show on list choice way, showing 8 monthes, 1 month to display on object page.
And my list choices display :

October 2012 /
December 2012 /
December 2012 /
January 2013 /
March 2013 /
March 2013 /
May 2013 /
May 2013
and July 2013.

I cleared the site cache and the browser cache.

Any idea of the origin of the problem ?

Hello,
please inform me about your version of Booking and Joomla.
On the current version of Booking (1.4.5) it seems to be working correctly.

Hello,

we never saw this problem. It is probably problem made by timezone settings or something else.

1. Did you modify timezone settings for server, php or Joomla?
2. Did you modify Booking component code?

I really don't know, where to start. Better will be if you send me admin details with url to your site to my email address Tato emailová adresa je chráněna před spamboty, abyste ji viděli, povolte JavaScript so I can check it myself.

Hello.
I use those timezone settings :

%d %b %G %H:%M for long format
%d %b %G for normal format
%d-%b for month calendar

The display I mentioned is precisely Janvier/2012 from the beginning. I didn't change anything.

yes, I customized some files.

EDIT : curiously, since we are in november, the problem is not showing anymore.
I'm still testing...

Hello,

problem was found. You had problem in 31.10.2012. Many months has not 31. and in code is bug.

I will try to send you solution soon.