A small problem with the Côte d'Ivoire
I'm guessing it's whether the particular sort implementation in each case is configured to be UTF8-aware. If I order by name asc in MySQL, I see Côte d'Ivoire just after Costa Rica. If I look at a hex dump of the actual bytes, ô expands to EF BF BD, which will appear long after o (6F) and even z if the sort isn't UTF8-aware. Have a look at the localisation configuration of PHP on your servers.

Sort order can be affected by cultural differences as you suspected, eg Swedish vs German at https://sgehrig.wordpress.com/2008/09/24/on-how-to-sort-an-array-of-utf-8-strings/