First add of my complication on apple watch is blank

I am developing an app with apple watch complications. When I first add one of the complication to the watch face it stays blank. When I tap on the complication the app opens and the complication on the watch face is displayed after closing the app again. Same behavior when I add a second complication on the same watch face or even another. Both the new and the old one is showing up.
Is there a problem with my timeline provider or are the API calls taking too long?

import WidgetKit
import CoreLocation

struct Provider: TimelineProvider {
    let locationManager = LocationManager()
    
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(date: .now, station: .placeholder, recentMeasurements: [])
    }
    
    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
		if context.isPreview {
			let station = Station.placeholder
			let recentMeasurements = Station.measurmentsPlaceholder
			let entry = SimpleEntry(date: .now, station: station, recentMeasurements: recentMeasurements)
			completion(entry)
		} else {
			Task {
				let station = await APIService.getStations().first!
				let recentMeasurements = await APIService.getStationMeasurements(station: station, days: 7)
				let entry = SimpleEntry(date: .now, station: station, recentMeasurements: recentMeasurements)
				completion(entry)
			}
		}
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<SimpleEntry>) -> ()) {
        Task {
            let stations = await APIService.getStations()
            let station = locationManager.getNearestStation(in: stations) ?? stations.first!
            let recentMeasurements = await APIService.getStationMeasurements(station: station, days: 7)
            let entry = SimpleEntry(date: .now, station: station, recentMeasurements: recentMeasurements)
			let secondEntry = SimpleEntry(date: .now.advanced(by: 60 * 30), station: station, recentMeasurements: recentMeasurements)

			let timeline = Timeline(entries: [entry, secondEntry], policy: .atEnd)
            completion(timeline)
        }
    }
}

Thanks in advance.

Edit (18.02.2023): Provider with Result

import WidgetKit
import CoreLocation

struct Provider: TimelineProvider {
    let locationManager = LocationManager()
    
    func placeholder(in context: Context) -> SimpleEntry {
		SimpleEntry(date: .now, station: .success(Station.placeholder), recentMeasurements: .success([]))
    }
    
    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
		if context.isPreview {
			let entry = SimpleEntry(date: .now, station: .success(Station.placeholder), recentMeasurements: .success(Station.measurmentsPlaceholder))
			completion(entry)
		} else {
			Task {
				guard let stations = try? await APIService.getStations(),
					  let station = stations.first
				else {
					completion(SimpleEntry(date: .now, station: .failure(ProviderError.stationFetch), recentMeasurements: .failure(ProviderError.stationFetch)))
					return
				}
				guard let recentMeasurements = try? await APIService.getStationMeasurements(station: station, days: 7)
				else {
					completion(SimpleEntry(date: .now, station: .failure(ProviderError.measurementsFetch), recentMeasurements: .failure(ProviderError.measurementsFetch)))
					return
				}
				let entry = SimpleEntry(date: .now, station: .success(station), recentMeasurements: .success(recentMeasurements))
				completion(entry)
			}
		}
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<SimpleEntry>) -> ()) {
        Task {
			let stationResult: Result<Station, Error>
			let station: Station?
			if let stations = try? await APIService.getStations() {
				station = locationManager.getNearestStation(in: stations) ?? stations.first!
				stationResult = .success(station!)
			}
			else {
				station = nil
				stationResult = .failure(ProviderError.stationFetch)
			}
			let recentMeasurements: Result<[Measurement], Error>
			if let result = try? await APIService.getStationMeasurements(station: station!, days: 7) {
				recentMeasurements = .success(result)
			}
			else {
				recentMeasurements = .failure(ProviderError.measurementsFetch)
			}
            let entry = SimpleEntry(date: .now, station: stationResult, recentMeasurements: recentMeasurements)
			let secondEntry = SimpleEntry(date: .now.advanced(by: 60 * 30), station: stationResult, recentMeasurements: recentMeasurements)

			let timeline = Timeline(entries: [entry, secondEntry], policy: .atEnd)
            completion(timeline)
        }
    }
}

enum ProviderError: Error {
	case stationFetch
	case measurementsFetch
}

Data fetching function:

static func getJSON<T: Decodable>(from path: String) async throws -> [T] {
    guard let url = URL(string: path) else { return [] }
		
	let (data, _) = try await URLSession.shared.data(from: url)
	let collection = try JSONDecoder().decode([T].self, from: data)
	return collection
}

There was an issue with filtering the data in the view.
Thanks for the help.