SwiftUI -> Thread 1: Fatal error: No observable object of type MyObject.Type found (EnvironmentObject in sheet)

You have to pass your environment object to BixiStationDetailView, otherwise it won’t have anything to bind to its @EnvironmentObject.

.sheet(isPresented: self.$isModalOpen) {
    BixiStationDetailView(station: self.station)
        .environmentObject(self.bixiModel)
}

Since you’re presenting BixiStationDetailView as a sheet, it isn’t a subview of your CardView and therefore doesn’t inherit its @EnvironmentObject.