Citi rule on downgrade card for Premier

[ficomember]

So Citi has the 24 month rule. Here's my history:

Got Citi Premier sign up bonus September 8 2019

Downgraded my old Premier October 2019 to Rewards plus

If I want the new Premier card, did that downgrade reset my 24 months rule to October 2021 to be eligible for the bonus again or not? I usually wait little bit but I have to apply this month for personal reason. So does it go with Sept or Oct? 

[yowhatimean]

I read somewhere that if you downgrade a Citi card, that the cycle restarts when the PC took place.