Sometimes it happens, but in the case of Accel, is that he always changes links, constantly, so the ones he sends to message to his patreons only work for so long, until he makes a new post of a new collection/work and thus, changing the links yet again, making the old ones obsolete. It's only in the very rare instances as people have seen with the collection links, in which through Kemono we get access to all it's content, but as he does constantly, once a new post is made, say goodbye to those prior links as they are, by then, no longer working.