Is "quest'isola" correct too? Thank you.
Yes, it would be very commonly truncated.
Why has Duolingo not corrected this for SEVEN years then? Do they even monitor these discussions?
They probably don't, but "quest'isola" has been accepted for at least 6 years.
But "bel porto" it's the same of "buon porto"!
why not buono porto?
Here is a link: https://forum.duolingo.com/comment/17416005/Buono-vs-Bravo-vs-Bello-vs-Bene