I can understand and appreciate an honest mistake. This was bound to happen eventually, and it's impressive it took us 133 editions for it to happen (so good going NSC).
But also, in future, can we please just not? This isn't ISC. Double checking the qualifiers is hosting 101. Triple checking your 10th placers in particular, and especially when there's only one point in it. In the worst case scenario, realising after the semi results and before the final and granting a 29th finalist doesn't hurt, but this situation way after everything has finished is a bit uncomfortable. We don't even have a protocol for it...
This isn't a read on the 133 hosting (although srsly wtf guys lol tbh). Like I said, it was going to happen someday eventually. But now that it has, can future hosts bear this in mind and take note on the fundamentals of hosting. Hosting isn't easy, but casting your eyes over your scoresheet to double check your qualifiers is. Don't get complacent ppl NONO