This is not a bug in Kentico, but an issue with the IP2Country.dat file that Kentico uses to resolve IP addresses into countries. It does not contain some recent IP address ranges for South Africa. (Are other countries having issues with it?)

I think this is the data that Kentico uses: http://ip-to-country.webhosting.info/node/view/6 - and you will see that it does not resolve the 41. IP ranges (e.g. 41.133.14.200)

If anyone else has diffuculty with this you can use the CSV file from http://software77.net/geo-ip/ which seems to work perfectly. I just needed to remove the extra columns and format it in the same way as the existing .dat file (which is actually a ZIP file containing a CSV) by adding quation marks as text qualifiers.