you mean a custom page error that redirects to an existing page?
No. For starters, appreciate that ordinarily, default 404 handling is this:
1) A user agent requests a URL
2) The server replies with 404 Not Found status - plus some human readable, bare bones text that the server returns to say to the person, the requested page was "not found."
When a custom 404 page is created to go beyond that bare bones text, many times the actual 404 response in the header gets dropped completely. The server admin or CMS programmer is so focused on the user's experience they forget about the HTTP header completely. So then the original request gets this response:
1) A 301 or 302 redirect status, and the redirect points the user agent to
2) A 200 status page delivered with human readable custom information
Notice what happened here. At no time did the user agent (e.g. googlebot) ever get a 404 status - it was never told the original URL is not there! Especially with 302 > 200 status, the potential for total havoc is strong.
This technical error (a soft 404) is so common that Google today tries to adjust for it - and they do at least some of the time. But when they don't, a site's search traffic can go belly up a few weeks later and the site owner has no clue why.
Getting your custom error pages to use the correct HTTP status can be a challenge, depending on your type of server and in some cases, your CMS. When you don't have admin access to the server, you can be in pickle. Sometimes, when a big web host does things wrong for hundreds of thousands of domains, Google catches that and compensates. Sometimes, but I wouldn't count on it.