Should a monster CR be recalculated if players have magic weapons to bypass monster resistance?

@RobertPascuttin @IAmTheImagineerShould a monster cr be recalculated if players have magic weapons to bypass monster resistance? No.

— Jeremy Crawford (@JeremyECrawford) October 18, 2016

@RobertPascuttin @IAmTheImagineerThx! Can u explain dmg; p277; para 3 then please? Seems 2 say having or not having magic weapon adjusts CR That's referring to things like spells or class features.

— Jeremy Crawford (@JeremyECrawford) October 18, 2016