This may be an unusual thing, but happened like this:

• I had started one repository (SVN) for a project, in order to store legacy code and keep its maintenance.
• Developers had solved some issues and committed code to that repository, linking the code to the issues (it was revision 6).

!Issue_revisions.png!

• For some reason, they messed up the code, so they decided to start a new repository from scratch (it would be easier than revert changes and so on).
• So I deleted the old repository and created a new one, where they committed the last changes on the code (making it revision 2 to 4).

!Repository.png!

• After that, the links of the issues were kept to the revision 6. Clicking on the revision 6 would still show the changes from the revision 6 of the old repository, even if the repository wasn't there anymore. But clicking on files or on the "diff revision" would show the error 404 "The entry or revision was not found in the repository.".

!Revision6.png!

After that, I tried to remove the repository settings from that project, and add it again, but I still had the same behavior.

I don't know exactly how Redmine keeps the repository information, but it seems to be storing old information on its database... Perhaps this may be solved by reloading the repository information once it's reconfigured on the project settings.