Public link is null

After doing GetSupergroupFullInfo on supergroup id = 1315078272(which is https://t.me/temalebedev), i'm getting null in the invtite link field:

Is that expected behaviour? Is there a way to get the invite link? The search results(with SearchPublicChat) does with contain channel username or a link either.

Always read the documentation! That field is only shown when you are the administrator of that group