Plate coral questions

I bought a plate a few months ago. It's a short tentacle plate and I feed it frozen and pellats. Today i noticed that 5 hours after I fed it pellates it seemed to vomit, for lack of a better word, the pellats back up. is this normal feeding habbits? Also the color is not super green it seems to have some brown areas. It has always been this way is this ok? I thought it was dying once because it closed up and shrivled for 2 days straight then it opened up with more tentacles than before. just curious because i grew very fond of my plate.

 

What brand are the pellets? If there's too much vegetable matter in that brand, I could see a coral spitting them out. Also, maybe it ate too much.

 

Are the pellets hard? I would suggest feeding zooplakton and mysis - or finer food particals.