Two quick suggestions:
If you're using custom identifiers for your articles, make sure you aren't using purely numeric identifiers. OJS will confuse these with the numeric identifiers it automatically generates. (Prefixing numeric custom identifiers with something, e.g. using
a123 instead of
123, will resolve this.)
If possible, upgrade to a newer release. It's likely that this might already be resolved. The current OJS 2.4.x release is 2.4.8-2, and the upgrade to that version should be low-impact. If you're ready and don't need features that aren't planned for release until OJS 3.1, consider upgrading to OJS 3.x. This will involve more of a learning curve, however, so I'd recommend running a test upgrade so that you can explore it a little before committing.
Public Knowledge Project Team