I downloaded it from the European Patent Office, but the pdf link that appeared on the webpage was always one article. No matter which patent I searched for, it always showed one article.

I tried it and there is no problem like you mentioned. After clicking download in the upper right corner, a verification box will appear. When downloading, choose to use IE to download, otherwise the download will be incomplete. PDF version 9.x, tested by World Window 2.4. This problem seems to be a caching problem. I guess you are using a proxy server. Please check the settings in this regard.