No, it isn't that. The data base contains all completed torrents of a member still listed on the site. Only the value of how many will be displayed in that list has been increased from 50 to 250. Mine was showing immediately more.
However, I've noticed some years back (2010?), when working to get the "lost torrents" from the spring 2009 server crash back, that from one day to another many torrent's completions lists (not visible any more to non-staff) became empty or very short. It looked for me as if some data base purging was done, but never got any confirmation from the Administrators.
@ric58hard: Do you have javascript enabled in your web-browser?