Nearly all the taxa I fixed have a (current) 7 digit GBIF number starting with a 9. At least this aspect of the problem is nonrandom! I have to wonder whether indexing changes were made at GBIF, causing the links to break.
If this were to become a bug report, our admins need something structured enough to tackle. How could this be formulated to make it productive? It looks to me like GBIF involvement is needed (if my hunch is correct).