We fixed the TypeError with an extension release but the app is still not connecting, invalid address errors in the console. There's nothing obviously wrong, just seems to be just a really badly written dapp. We suggest talking to the dapp developers in the first instance regarding supporting non-MM wallets.

‘Switch to Matic’ button connects in Frame but spins endlessly. Console error seems to imply they are using internal metamask functionality:

Page connects automatically to MM on load.