Trophy Bug: Unable to get trophies in coop mode

How do you get trophies for hard levels in coop? My wife and I have completed the levels in coop mode for multiple times and we get a trophy at the end of the level every time. But the problem is it never shows up on the level selection menu. Don't know why.

Another interesting thing I find is when we finish a hard level in coop mode, the game will go back to survival menu instead of coop menu. So I think it is a bug that we couldn't get the trophies for hard levels in coop since the game recognises the coop hard level as survival hard level.

Please fix this!