Inconsistent Inventory/Wish List Button Feedback

[theplanets]

I've noticed that there's inconsistent feedback with the Add to Inventory/Wishlist buttons. On many pages (eg Minolta 35 original), clicking the button does not change the response to "(you added 1)" and will not be reflected under the camera photo - "Camera featured in these collections:" or "Camera is in these wishlists:".

I've seen it on random camera pages and not sure what causes it.