Remote desktop folder and offline files

Question

I have the following problem in the institution I'm working in. So we've set the users folders to be hosted on \server\Users\%username% folder, from their AD user settings and the folders are got copied to the server. The offline files are turned on, but we have problem on some computers, that the files never were offline before. Example: we've got one of our PCs changed recently and account, we're 4 people that use that PC but we also use other PCs. On the new PC, the desktop icons sometimes disappear and reappear after some time, the Task bar also doesn't work properly. When the icons disappear, we get message that we don't have connection with the remote folder if we try to do something with the files (save opened file, create new file). The offline files are turned on, and we've set it so they can't be turned off, but for some reason it seems like the files aren't really downloaded and accessed offline. On the other PCs we use there's no such problem, but the desktops there were created before the policy for the remote folder, so if we change or reinstall them, they'll most likely have the same problem. Do you know any solution to this problem?