Ok so after much confusion I can now replicate this - make several identical devices on different tracks and set up parameters differently on each.
Now edit one device in Max for Live, and when it asks say "Update all". With my particular device, the key parameters are now reset and useless across all the tracks.
However if I just 'save' the patch for one track, and then use 'hot-swap' mode to update all the other devices to the latest version, the parameters are transferred OK. What gives!? Can you replicate?