Sometimes the shape-shifting of the organization can feel a little sloppy and folks will get "left behind" in awkward re-arrangements of teams. I've seen this happen quite a few times, and know first hand how jarring it can be to have a new manager suddenly without a warning.
With that said, Toast is a young start-up and these events sort of come with that package. As the companies continues to mature, hopefully so will its communication process with its employees of all levels.