I would agree, but if so, I'm surprised not to see partitive case used, since it's a generality.
I just got dinged for translating it as "THE dark Finnish bread...", and I'm not sure why that isn't acceptible, since there's no partitive (except that hyvää) to tell me we're talking about dark Finnish bread in general. Shouldn't it be tummaa suomalainen(a?) leipää? If the hyvää is the only cue needed to express that generality, I'm back to being a bit lost about partitive.
I think about it as follows. The subject is Finnish bread. The property attached to the FInnish bread is light or dark. Whether in English or in my own language, it makes more sense to prepend the word dark to Finnish bread.
The alternative is to regard all the dark breads in the world and add whether it is a Swedish, Brittish or Finnish dark bread.
I saw the downvote on this question. Unless the question is offensive or obscene, never downvote a question. Even if you don't agree with the contents. A downvote of -5 makes the question practically invisible. I did an uptick to prevent the vote from being below zero.
I wrote accidentally hyvä, which I guess is wrong, but it was accepted, even without a typo message. I guess it's a problem with Duolingo, not just this course? Previously, typos that transformed words into another meaningful words were not accepted at all. Anyway, I reported this as My answer shouldn't be accepted.
You definitely can say "tämä on hyvä leipä" (singular) or "tämä on hyvää leipää" (mass noun). But the example is structured "this bread is good", as it tastes good, so you need the extra "ä" on there, to make sure you are talking about the taste. If you say "tämä leipä on hyvä", then the bread is good in some other way, like it meets the speciefied shape standards or something, but it doesn't refer the taste. But usually people are talking about the taste, therefore "hyvää" sounds to fit better in here
I think because "tumma" comes before "suomalainen leipä": tumma suomalainen leipä rather than suomalainen tumma leipä, makes it "dark Finnish bread" rather than "Finnish dark bread" --therefore Finnish bread that is dark, rather than dark bread that is Finnish.
It's a similar sort of consideration as for where in the sentence todella falls.