The "Contribute Max" button on the guild task screen doesn't have any confirmation. Not sure if that was intentional, but it seems rather dangerous as a mispress could cost you tons of gold.
Also, first definite bug I've found, in the guild menu, on the roster view, when you click on a player's name it has a little box on the right hand side pop up with options to promote/demote/kick etc.
This box is not functioning as intended. It appears as if the box only appears off-screen when you choose lower players on the list. Higher players on the list will have it show up properly. I recorded a video of this but it will take a bit to upload.