Just for info:

My installer 'fixed' the erratic behavior of my MX-900 simply by
uploading the configuration file from the remote and re-downloading
it with his current version of the editor. He said that he noticed a delay before the re-downloading, which indicated to him that the firmware in the remote was being updated.

We knew immediately that the problem was solved, because prior
to the re-download, pressing the ON button resulted in "macro"
flashing for 20 seconds, and after the re-download it flashed only briefly.