Steps to reproduce:
1. Upload a file using the default workflow
2. Untick the archive option
3. Inspect workflow and look at the configuration
archiveOp is not present
archiveOp = false
Though not unset is equivalent to false, this can cause problems if you have an operation that sets default values for config properties if they are unset, as false will always be overrided by the default.
Scheduling the workflow appears to correct add archiveOp=false