I had the same concern. But, in the datamine, you can actually see Halsin’s dialogue differs depending on whether or not you’ve lifted the Shadow Curse. This is my speculation so take it with a grain of salt, but I think in order to lift the Shadow Curse and get Minthara, you will have to help Halsin first before rescuing Minthara in Moonrise Towers.
I predict this will be an issue for most players if there is no warning beforehand. Hopefully Larian considers a few things before implementing it in a future patch. People have also heavily criticized the dialogue itself because they think it’s out-of-character for Halsin to issue an ultimatum and condemn Minthara to mind control.
