Custom 404 error not working on dynamic page

I have just noticed that the custom 404 message doesn’t appear to be working on all pages.

Is this correct? If so, my options appear to be to add a router for jobs to check that the id is valid before I forward to the page. This seems like overkill. Any advice?

Matt, even on a static page, the custom 404 is a buggy feature, and I’ll recommend not to use it.
They just didn’t QA it enough.

Wix is so good and so bad all rolled in to one.

See here the previous thread regarding 404 issues:
https://www.wix.com/corvid/forum/community-discussion/custom-404-page-issue