Turns out somehow wp-content\languages\plugins\all-in-one-seo-pack-zh_CN.po is dated 2021/8/1, must be a left over from one of the old versions we installed. Removing all all-in-one-seo-pack-zh_CN* files in that folder, and paste manually with the .po/.mo/json file I freshly installed from another machine will not see the problem. The newly copied file is dated 2022/6/4
