At the historical museum – dative or accusative?

Last Sunday (not this Sunday, but the one before), I went with a student and her boyfriend to das Deutsche Historische Museum. It is on Berlin’s main boulevard "Unter den Linden." The building is centuries old and big. Because it is also heavy with history it rarely moves around. In fact, it has not moved around for many years. Old Berliners I asked told me that they have never seen the museum on another place. That’s why it is in a state of dative. That’s why the street name has not changed. Would the museum have moved out of the street and then back into the street, dozens of (uniformed!) street sign administrators of the city of Berlin would have replaced the street signs "Unter den Linden" with an accusative "Unter die Linden."

die Linde = linden tree [bot]
plural, nominative, accusative: die Linden
plural dative: den Linden

The exhibition of the museum is about history and not about grammar, of course, but the panels explaining historical events should incorporate some grammatical rules.
After we sailed easily through the dark ages and survived the reformation, we got stuck at the Thirty Year’s War, more precisely at the panel about the war. It is depicted in the photograph above.
It is a great achievement of the panel’s author to use only a few words for such a long war. However, in my opinion he or she used too many adjectives and therefore, he or she got caught in the middle of the eternal battle between accusative and dative. We noticed the following sentence:

"Der religiöse Charakter des Krieges trat zunehmend hinter massiven machtpolitische Interessen zurück."

The author tells us that at the beginning the war was fought over religion. With the years, the religious character disappeared "increasingly" (zunehmend) behind huge power-political interests. We stumbled over two adjectives in that sentence, "massiven" and "machtpolitische." They are attributed to one and the same plural noun, Interessen (sing.: das Interesse). Following the tradition of the Thirty Year’s War, they do not like each other and they do not agree. However, following the German grammar rules they should. One – massiven – is in dative, one – machtpolitische – is in accusative. What happened?

The subject of the sentence, the religious character is moving, namely behind the huge power-political interests.

…trat hinter … zurück, zurücktreten hinter = to take second place to sth. (according the Oxford Duden German Dictionary)

Was it "in front of" the Machtpolitik, and then stepped around to get behind the Machtpolitik (movement = accusative)? In that case the author is convinced that in the beginning the religious reasoning for that war was real and that the fighting parties spoke the truth when they took up arms. Then, with time, power politics took over and the fighting parties pursued nothing else than power.

Or was it always behind the Machtpolitik (location = dative) and in the author’s eyes only a pretext for the war and as such fading with the years?
With one adjective ending (massiven, dative) the author seems to think one thing, with the other (machtpolitische, accusative) the other. Maybe, he or she was not sure.

I read in the Duden, the most important dictionary of the German language, that the phrase "zurücktreten hinter" always leads to a dative, no matter what intricacies we want to express.
Another explanation for the disagreement of the adjectives could be the missing comma between them. The author does not say that the interests were huge and power-political (the "and" can be replaced by a comma). He or she says that the interests were power-political anyway, but huge (and not small).
Nevertheless, the adjectives must agree, and "machtpolitische" needs an "n" at its end. There is nothing we can do about it except get rid of the adjectives themselves and replace them with verbs or nouns or with nothing at all.
Mark Twain said, "if you catch an adjective, kill it!" Done.