When working with documents outside of Meridian, you might be accustomed to creating a copy of one revision in order to make a new revision of it. Meridian works this way too when you make a project copy of a master document. When you release the project copy, it replaces the previous released revision of the master document.
But if you make a copy of a project copy instead of from a master document, the copy will not become a new revision of its source document. It will become a new revision of the master document from which the source document was copied. This might not be what you intended to do.
Meridian allows concurrent engineering by making revisions to parallel copies of the same master document, not by replicating changes in successive copies as you might do for documents outside of Meridian.
For more information about making project copies, see Copying a master document to a project folder.