This is a TV character showing up in another TV show. Coulson or Daisy coming in to The Defenders.Nope, with Feige too. Hence why Disney gave Feige direct control of Marvel Studios/film production and removed Perlmutter from the film equation entirely, which created bad blood with Perlmutter.
Nothing other than that they're all under same Disney corporate umbrella. That was sort of the point, along with fact Feige won't work with Perlmutter anymore (his interference in Phase 1 films was notorious), and Perlmutter is notoriously petty, so probably would stand in way of the TV characters showing up in films.
It's all just a multi-billion dollar pissing contest, after all.