Which Sitecore version are you using?
Do you make the version in exactly the same language as the version you expect the values to be?
How do you create the version? Do you use a workflow to create a new version?. is it working well when u use the Add button in the versions topbar-tab?
Are there any custom events in the config, in events like <event name="item:versionAdding"> or <event name="item:saving"> (a admin can see the config with /sitecore/admin/showconfig.aspx on CM server)