~~If there is some problem generating links to comments by people outside kbin, I would suggest that notifications should link back to my comment that they are responding to. For the above example, more > share URL for my comment is https://kbin.social/m/reddit@lemmy.world/t/152720/-/comment/659758, which works properly. At least it is a little closer to the target.~~ Edited out because this does not help actually. And edited the title to remove reference to this.
I may be misunderstanding this, but it sounds like you're running up against this bug where notifications don't work if the comment they reference is not on the first page of comments.
however this issue is not limited to notifications, because if you use "share url" from the comment itself, it will give you the link without the pagination.