Smart notification missing on iOS

For the last couple of week there has been a problem with iOS smart notifications. Every now and then the notification is missing the small preview image on my iPhone. However, when long pressing the notification I get the image on a larger size. Then after I restart my iPhone I get all the images correctly for some time (also the past missing images reappear on my Notification Center!) and then the problem reappears after some time.The problems comes and goes also on my iPad Pro. Even when I do not get the preview image on my iPhone the same notification image might show on my iPad. All hardware are running the latest firmware. The Ring app is the latest version. How should I correct this problem? I am using the Ring Doorbell 3 Plus.