Primary image doesn't show up as a poster

For some inexplicable reason an image uploaded as a poster stopped being a primary image. Upon trying to set it up as a primary image it says it still is one. https://www.imdb.com/title/tt22078210/mediaviewer/rm1413982466/ Might be a temporary issue but doesn't look like the other common primary image display issues (early failure to appear in lists, for example).