The next significant update to the Unread for macOS beta will include a big change to keyboard shortcuts. The ⌘M keyboard shortcut will no longer mark the current article read or unread. The ⌘M keyboard shortcut is a standard macOS keyboard shortcut for minimizing the current window. It needs to work in Unread just as it does in other Mac apps.

Going forward ⌘⇧U will be the keyboard shortcut for marking the current article read or unread. That keyboard shortcut already works in the current beta, so you can start using it now.