What happens if a kalashtar eats a dream pastry?

According to Eberron: Rising from the Last War:

Kalashtar sleep, but they don’t connect to the plane of dreams as other creatures do. Instead, their minds draw from the memories of their otherworldly spirit while they sleep. As such, you are immune to spells and other magical effects that require you to dream, like dream, but not to spells and other magical effects that put you to sleep, like sleep.

Meanwhile, for dream pastries (Curse of Strahd, chap. 6):

A creature that eats one in its entirety must suc­ceed on a DC 16 Constitution saving throw or fall into a trance that lasts for 1d4 + 4 hours, during which time the creature is incapacitated and has a speed of O feet. The trance ends if the affected creature takes any dam­age or if someone else uses an action to shake the crea­ture out of its stupor.

While in the trance, the creature dreams of being in some joyous place, far removed from the evils of the world. The places and characters in the dream are vivid and believable, and when the dream ends, the affected creature experiences a longing to return to the place.

So what happens if a kalashtar eats a dream pastry? Obviously they don’t dream. Do they fall into the trance? If so, what do they experience?

Alternately put, does the dream pastry’s trance require the dream, or are trance and dream mechanically separate (though related)? If they are separate, what happens to a kalashtar when they eat one?

A PC in Curse of Strahd is cursed by Mother Night and eats a dream pastry. What happens?

A PC in Curse of Strahd has the opportunity to be cursed by Mother Night, at which point they are

On the other hand, a PC who eats a dream pastry

As luck would have it, one of the PCs in my current CoS campaign has been cursed, although he has not yet slept. He is also the only PC to have previously eaten a dream pastry. If he realizes the effects of the curse and decides to counteract it with a dream pastry, what would happen?