As this just happened to me after having last played when Super Adventure Box was out, I came to the forum and found your post, then looked further in the sub-forum.
This was mentioned as possible “fix” for when this happens, but the Devs say to wait it out….
https://forum-en.gw2archive.eu/forum/support/tech/Possible-fix-for-problem-downloads-patches/first#post2053337
took me about 10-15 minutes of waiting, btw. vs. switching languages.