Seyfert galaxies are thought to be undergoing very violent processes. Does that mean they are still evolving?
Seyfert galaxies are galaxies with active nuclei.
A Seyfert galaxy is a galaxy with an active nucleus. There is a supermassive black hole at the centre of most large galaxies. If material falls into the black hole it forms an accretion disc. Material falling into the accretion disc gets super heated by friction and gravitational effects. The super heated material emits radiation to become an active galactic nucleus. Quasars and Seyfert galaxies are undergoing this process.
Other than being very bright and having an active nucleus, Seyfert galaxies are otherwise like regular galaxies. They evolve as stars die and new stars are formed.
Once the material falling into the central supermassive black hole runs out, the galaxy ceases to be a Seyfert galaxy which is part of its evolution. A galactic nucleus can also become active if there is enough material in the vicinity of the supermassive black hole to power the process.