If you call multiple BitmapImages at once, some of them get stuck in the download process, and the image won't be displayed in the UI

Question

I have multiple Images in my Window. Every single one of them download another image at the same time.

<Image Source="{Binding Converter={StaticResource cachedImgConv},IsAsync=True}" Stretch="UniformToFill"/>

Inside the Converter i download with a BitmapImage:

var image = new BitmapImage();
            image.BeginInit();
            image.CacheOption = BitmapCacheOption.OnLoad;
            image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
            image.UriSource = new Uri(uri);
            image.EndInit();

return image;

This works well so far. All images are downloaded and displayed in the UI. Unless the number of images reaches something like 20 and above. Then some BitmapImage get stuck in the download process.

I tried to use different CacheOptions and CreateOptions from the BitmapImage. To use in Xaml "IsAsync" true and false.