Here it is.
We have quotas and visas issued. Quotas for Poland and NA were filled sometime in March. I suspect some interviews in March were cancelled. Quotas were filled and no more visas were issued. For SA it was different. Quota was filled May, some interviews were probably cancelled in May, no interviews were done in June July and August. But in September things changed. EU was still Current, because there were not enough available applicants. That was the only region current. Too many winners were from Poland, and Polish per country quota was exhausted. The rest of Europe did not have enough applicants. So, Europe got only 24289 visas, but the quota was 24549. The extra 260 quota units were transferred from Europe to other regions (except NA) in September. NA did not get any because it's share was less than 1 visa. Other regions got extra quota.
Totally, blue regions were underfilled, and red ones were overfilled. I have no idea why OC and NA were underfilled. The whole world got 55058 visas, that was more than quota. I suspect they issued 58 extra visas to family members of winners who submitted late, after other family members go visas. But the idea is clear. They made a mistake with Poland, so Europe did not have enough applicants from other countries, and the could not fill visas for EU. So the waited until September and transferred 260 extra visas to other region. AF quota exceeded with 114 visas, AS with 27, and SA with 196 ones.