"as regards the earlier similar registrations relied on by the applicant, the Board of Appeal recalled that those registrations did not represent current practice and case-law and that the legality of the decisions of the Boards of Appeal must be assessed solely on the basis of Regulation 2017/1001 and not on the basis of a previous administrative practice."

Precedence in court decisions is weighted more in some places than others. US courts, from my pedestrian observation, are all into "well there is a precedent so we'll follow that". But other countries don't necessarily do that, their courts might be more eager to disregard it and do whatever they feel is appropriate in that situation. You can see it in how OpenAI reacted "The company also cited comparable trademark registrations previously granted by the EUIPO and registrations in more than 30 other countries, including the United Kingdom and Singapore" (well precedents say this and that...)

edit: I originally thought that’s what was being rejected here. It’s not. The court only ruled that “OpenAI” is descriptive. Separately, OpenAI have also submitted evidence of acquired distinctiveness, which will be decided in due course by the trademark office.