I've seen this happen a few times now. I use Advanced Search to find a thread to which I contributed but, when I go to the thread, all content is missing. An example is To lie to DH and get all vaccines for baby? | Mumsnet. The thread hasn't been deleted. It apparently has 38 pages of content. However, neither the OP nor any of the other contributions are displayed. I can navigate around the pages, but all are the same. I've tried logging out and I've tried a different browser with the same results. Looks like a bug.