NPrinting 17.5: reports are not saved in local folders when the destination contains a Qlik variable

NPrinting 17.5 is set up to run tasks that save the reports automatically in a specific folder.
The path of the folder is defined in a Destination and it contains a Qlik Variable.
The task is run, but the reports are never saved in the local folder. They are sent correctly by e-mail.
Reviewing the the Executions page shows that the task is in Completed status or that it is running but has reached 100% of execution.
 

The Scheduler log file print the following error message:

ERROR    ITVIC-ARZ    Nprinting Task Identity    0    0    0    0    0    0    0    0    Impossible to save report in folder C:\Test\01205305\%%QV_d45edc4369b14f9f90e15b539b2db596_vDay%%    Folder path contains unresolved variables

This problem to a bug introduced in version 17.5 ( OP-6259 ).

This problem is due to a bug introduced in version 17.5 ( OP-6259 ) this will be resolved in version 17.6. Due to the relevance of the issue a solution will be present also in the NPrinting 17.6 technical preview that is planned to be released at the beginning of October 2017.
The best solution is to upgrade as soon as possible.

The only temporary workaround is to remove the variable from the path definition in the Destinations.