Moderator, Marriott Bonvoy & FlyerTalk Evangelist
Join Date: Oct 2002
Location: McKinney, TX, USA
Programs: United Silver; AA Plat/2MM; Marriott LT Titanium; Hilton Gold
Posts: 11,727
Per my past experience, the nights of your stay in 2020 will post to this year. The 2021 nights of your stay will post to that year. So the answer is night credits will be split between the years.