1 - at that time, the CEC candidates above 470 kept leaving the pool every 2 weeks. Also, IELTS were not available everywhere. That’s why it remained “under control” even with 6 months of CEC only draws.
2 - The reason for 478 is a mix of a 3 week buffer in the pool (something that didn’t happen in any of the CEC/PNP draws), and specially, the 1000 PNPs. Previous draws were ranging from 300-500 PNPs, this one had 1000!
3 - Again, official data from IRCC: only 4% of candidates in the pool speak French, less than 2.8% of candidates that get PR speak French, probably half of these 2.8% are not bilingual, but actually people who came from French-speaking countries with no much knowledge of English. That means, let’s say, 1.5% of the candidates who received ITAs in 2019 were bilingual. That’s a very small number. Add to that the fact that those who were bilingual already had 30 bonus points before the change in the CRS Criteria. It’s very unlikely these candidates weren’t already at the upper 480’s. Myself, being bilingual in French and English, received my ITA sitting at 508 (would be 528 in the new criteria). You see? For these candidates, these 20 extra points really didn’t matter.