We are working on a game that uses "scenario files" to define a series of game scenarios to be played. These are stored in a scenario folder, which is part of that package that Butler routinely uploads and updates to our itch.io channel.

As the game is still in development, the content of the scenario folder changes frequently: scenarios are added, modified, renamed, and deleted.

Most of the time this all works flawlessly, but we are noticing that under some circumstances, we will have one or more scenario deleted from the master code set that Butler is pushing up to itch.io, and yet those files are NOT deleted in the clients' local itch.io app data folders. So those users are left with "legacy" scenario files in their local itch.io installs that should have been deleted during a prior update but were left installed.

Why does this happen, and how can this be rectified?