For me appear for a second the fields and then disappear. Only when I use it stays. Maybe after first use is something in the browser cache?
We query the ln addr provider every time you change the address, character by character. We probably need to debounce this, because if you're on the second to last character, there won't be valid metadata (e.g., so we default the form state. If these requests resolve out of order, you could end up in a state with no LUD-12 or LUD-18 options in the form. Debouncing should resolve it.