This is interesting information: The results of the poll numbers for this one representative look more like the poll numbers for a run-of-the-mill president, rather than a politician from Hawaii. As you can see from the other polls, the "other three" have way more lopsided poll numbers than Tulsi does. 
I'll go out on a limb here in interpretation by saying that the results are in direct relation to the level of game that Tulsi is playing in Washington. While she is representing her people, she is also engaged in a much higher game than just the internal baseball that, say, Schatz plays in the Senate (leadership positions more than taking national stances). 
So comparing the three to the one (Tulsi with the rest of the Hawaii Congressional Delegation) is a bit like comparing apples and oranges. And I think the people polled in this see that difference, and have reacted, accordingly. We will see if the support stays in the long term.