When a member uploaded images with a spoiler tag applied, the images were fully visible. When I go to edit the post, the preview shows the images as correctly blurred, but the images keep being openly visible.
AI-generated summary
The discussion is about a spoiler tag not working correctly. TheOtakuBox reported that when a member uploaded images with a spoiler tag, the images were fully visible, but the preview showed them as correctly blurred. JammyDodger tested the issue and found that the problem occurs when there are two images. Moin confirmed this and provided examples of the spoiler tag format. JammyDodger explained that to fix the issue, either each image must be wrapped separately or the wraps must be on their own lines for both images to be covered. TheOtakuBox thanked everyone for the clarification.
Seems you use two images
[spoiler]
[/spoiler]
So the problem is reproducible, if two images are used.
Nice catch @moin 
For more than one image on separate lines I think you either have to wrap them separately for individual blurring, or have the wraps on their own lines like this for them both to be covered:
[spoiler]
[/spoiler]
Thank you all for the clarification!