Browse node randomly changes to unrelated category

Why do browse nodes change randomly, and are difficult to change back? I've been selling posters on Amazon for over 10 years and they've always been categorized "Home & Kitchen › Wall Art › Posters & Prints". Some time in recent weeks, one of my posters changed to "Office Product", in the same category as staplers and scanners. Now, two more posters were changed to the "Books" category. When I try the node change process in the Help section, I get a response that the case was reviewed and determined that the new nodes were correct. What? The posters are neither office products or books. Anyone have a suggestion? Thank you!

Also, when the node changes to a non-poster node, the products are no longer 'feature offers'. That's when people stop seeing them when they search for the posters.