When making a payment to a lnurl, it does not throw the success notification [top right corner], and it goes back to the view where the previous sending amount is pre-filled.
It looks like the payment failed, but in fact it was successful.
Combining this with the fact that it's possible to make multiple payments to the same lnurl, the user might make multiple payments, even though he only wanted to make one.
When making a payment to a lnurl, it does not throw the success notification [top right corner], and it goes back to the view where the previous sending amount is pre-filled.
It looks like the payment failed, but in fact it was successful.
Combining this with the fact that it's possible to make multiple payments to the same lnurl, the user might make multiple payments, even though he only wanted to make one.