Repeater items can have a max and min height, preferably the latter, but they are determined by their content. Are you trying to achieve a Mosaic-effect? Or do you just want that the item on the bottom left to have its bottom edge up against the bottom of its content.
I would have the item have a grid with min-max settings, where the min don’t exceed say 50px. Then make sure you item container doesn’t have a min height, which it looks like it would there.