It was announced through the official website that some Attack on Titan merchandise was deemed too sensitive for sale. That merchandise pertains to the Eldian armbands which are said to promote discrimination and are a symbol of oppression. They began to accept pre-orders back on Sunday; however, that is no longer the case.
This comes after series creator Hajime Isayama faced backlash for one of the story arcs involving the Eldians and the Marleyans. Some claimed that the story had fascist subtext to it which incited a short-lived response with people attempting to protest the series.
While the story went on as planned without alteration or interruption, the armbands; however, did not.
You can see a depiction of the merchandise that was slated to be sold below:
Source: Comicbook.com