implement a meaningful page to put at that link (little bit of dev time, ideally push to Jonny who’s already familiar with the code, although I could look into it if that’s not an option) or
remove the link from that breadcrumb (so it just says Blogs and doesn’t lead anywhere - I did this for Authors , but I had a quick look & it seemed more fiddly for this link than for the Authors link so backed out of it)
e.g. https://www.thedatalab.org/blog/2020/10/159/what-is-opensafely/ has breadcrumbs
Home > Blogs >
, and the Blogs link is a 404.