You're pretty advanced, Ian-the-destroyer
1700 beats a cm

non official V. category of ELO 1000
IV. category of ELO 1200
III. category of ELO 1400
II. category of ELO 1600
I. category of ELO 1800
CM ( candidate master ) of ELO 2000
NM ( national master ) of ELO 2200
FM ( FIDE master ) of ELO 2300
IM ( international master ) of ELO 2400 ( achieveing 3 norms )
GM ( gros master ) of ELO 2500 ( achieveing 3 norms )
non official EM ( Elite Master ) of ELO 2700

cm is not 2000 its 2200
2200 by American rating ,
2000 by FIDE rating
Do FIDE something changed about definition of title rating in 2023 year ?
https://handbook.fide.com/chapter/B012023
FIDE Title Regulations effective from 1 January 2023 till 31 December 2023 /
Something like 2200
so like a 500 point upset