Honestly not surprised. Rebellion did feel a bit like it was setting up sequels for a series that didn't need them. Narratively the show as done, even Rebellion was already pushing it. They had to rollback the achievements, had to make Homura's tragedy into a failure and not a win, just to get those movies out the door. It always felt like they were milking a cow so I'm not at all surprised to see it continued. I'm just surprised it took this long.
Anyway, as the sucker I am, I'll probably still watch it. But I'll complain along the way