In general it could well be there is a second version with the oher disc ID. But the time difference is huge enough that this really should be separated, if it exists. And given the fact that you originally added this, yours is by definition more correct, matching the original recording lengths you entered.
Another (weak) indicator might be checking freedb (http://www.freedb.org/freedb_discid_check.php) which lists a different release for the longer disc ID (I can't really believe I used FreeDB as a source )
So I would remove the mismatched disc ID.