When a membership program is created, a campaign can be associated with that program so that any revenue applied to a constituents' membership will list that specific campaign. There is a global change process in Administration that allows users to update the campaign associated with a membership program. However, in specific situations existing campaigns may be deleted from membership payments by running the global change, and the only way to add them back to the revenue is via the backend tables or on a one-off basis from the revenue records.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.