Played DLC Op Spearbreaker, but now it's locked

Excuse me I’d like to know what is going on here, please.
I’ve purchased the Ultimate Edition of Halo Wars 2 and played the game through once including Operation Spearbreaker.
Now I wanted to play the game again on the next difficulty and discovered that Spearbreaker is locked behind a pay wall!

Spearbreaker is part of the Season Pass and I have already played it. Why is locked behind a pay wall all of a sudden?!?

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Update: 12/31/2018
Well, today I logged in again and wow! Suddenly Operation Spearbreaker isn’t greyed out and locked anymore.
To be honest, this kinda scares me. What happens if I should purchase Awakening the Nightmare someday? Is it going to be playable only once before it gets locked, too?
I’m not sure if it’s worth my money when I have to fear that the DLC I might purchase or even the extra money I payed for expansions of the Ultimate Edition are not accessible to me.