Dogmas have changed or been slightly modified by interpretation over time.
Witness the new movement for a dogma that Mary is a co-redemprix with Jesus Christ, or the various other Marian dogmas that came into officialdom circa 1950.
They are late dogmas indeed, but they are not examples of a changed dogma. For example, the bodily assumption of Mary has been a belief since the early days, but it was not elevated to dogma till late. It is not like people used to dogmatically believe one thing about the assumption and later they were asked to believe a different dogma. They are examples of a longstanding belief recognized as being historically accurate, that is, dogmatic.
In case of Mary as co-redemptrix, it is not likely that it ever will become a dogma, because the term is not well-defined. Perhaps one day there will be a clarification in what sense she is a co-redemptrix and in what sense she isn’t.