There appears to be a bug in version 2.3.8.1 which prevents the automatic inclusion of races when they fall into December.
This is fixed in version 2.3.9.1 - please see the New Releases forum at viewtopic.php?f=2&t=154 - so please ensure that you download and install the new version.
If you don't install the new version, you will have to manually include the races on the race grid by ticking on the left hand check box for each race. Remember you can select/deselect all races by clicking on the blank column header.
Please accept my apologies for the inconvenience.
Alistair