I realize I'm saying some stuff that has been said already but since our product manager appears to be Karen Ramrod.
Mobile in general but layout, quotes, and typing poasts in general are really bad. Usability is really suffering.
Typing on mobile is especially awful, it's doing it as I type this now. Jumps around where typing is landing seemingly randomly, deletes content that has been typed already, etc. Can't @people 81% of the tim for seemingly no reason. Combine it with the terrible quote function and it makes typing anything meaningful a gamble not worth investing time in.
Fix basic typing, quoting, and @'s on mobile (in that order) and at least you have a usable product again. Layout can come later.