Problem with shared folders

In an earlier thread I asked a question about users who missed some folders after creating a new replica of their mailfile to an other server. This server is the server for webmail. All the conditions which can cause the loss of the folders are false: no corruption, no private folders, in Design the folders are checked to NOT refresh design.

In the mailfile there is a column in the view @All (All Documents), which displays the folder in which the document is (formula: @WhichFolders).

Today I saw a strange thing: In the original mailfile this column displays the foldername if a document is in a folder. In the mailfile not any foldername is displayed in the folder-column, even when I move a document to a folder.

It does not matter if I upgraded the folder design no 8.5.1 or not (tested it).

Has this something to do with the lost folders?

Koos van Harmelen