hyphens and justify are only applied for paragraphs (for example, proofs in the docs are not justified). This is going to affect also to the sidenotes, depending if they are inside a paragraph.
I'm not sure if this is intentional, but, in this case, you would need to add a paragraph as the first element of a proof environment (if you want the text justified), or you will get a mix of justified/unjustified lines in the same proof.
hyphensandjustifyare only applied for paragraphs (for example, proofs in the docs are not justified). This is going to affect also to the sidenotes, depending if they are inside a paragraph. I'm not sure if this is intentional, but, in this case, you would need to add a paragraph as the first element of a proof environment (if you want the text justified), or you will get a mix of justified/unjustified lines in the same proof.This is in some way related to the closed PR #56.