Chroma subsampling and upscaling?

i’ve been upscaling vids for a while, but only recently i noticed something when exporting videos to h.264 crf=0 format - even though the source was 4:2:0, the output was 4:4:4
maybe a stupid question, but does upscaling also restore color information that would justify saving output videos with higher chroma subsampling than their inputs?: