Polystralia is supposed to get +2 trade routes in their capital. They still do, initially - but the patch having changed it so that more trade route slots unlock at certain city sizes (10, 21, 34) does not take the unique ability into account. This means Polystralia still only gets 3 routes (rather than 4) in their capital at size 10. They do not unlock their fourth route until size 34. Moderator Action: Moved to bug reports.