There's probably a word I've been pronouncing wrong my whole life that I don't know about
Just based on how often I notice someone mispronounce a word without realizing it (or have done so myself and realized it later). Statistically I'm probably still doing it with some word.
The d before n is inherited from the original name Wodans dag (like Tiu's dag, Thor's dag and Frey's dag inherited through the Saxons and Danes from pagan germanic gods)
The rest is just linguistic shift through the centuries of changing language. Like Dag -> Day while for example in German Dag -> Tag.
But the root of the word is still Wodan then old english Weoden then Wedn.