Can't get PPSSPP to launch from Lutris

So, I installed PPSSPP through the Flatpak distribution, and thought it’d be useful to set it up on Lutris. However, I can’t get it to work, and oddly enough, I can’t even open the configuration window after closing it for the first time. I select the Flatpak runner, provide the application ID (org.ppsspp.PPSSPP), the architecture (x86_64), the branch (stable), and the install type (system). The runner itself doesn’t give me any options. Then, when I try to run it, it gives me a pop up window that says ‘install_type’ and nothing else, and doesn’t actually launch. Also, right-clicking on it and selecting Configure doesn’t do anything, either. Does anyone know how to fix all this?