Trying to synchronize files with the percent(%) character in the filename would generate the error:
YYYY-MM-DD HH:MM:SS,sss [batch-monitor-pool-a-thread-b] ERROR vyre.marchena.engine.transport.download.AbstractDownloadHelper - An unexpected error ocurred when downloading the file.
This issue was fixed in Telescope Standard 2020.1 and it is recommended to upgrade your Telescope version to this or later to fix this issue. If your Telescope installation has customizations or you're an OnDemand customer, please contact your Account Manager or support for help with upgrading.
Transformation Platform should have no issues synchronizing files with the % sign in their filenames.