F5 iApp Automated Backup

Hello, I a using v3.1.3. When I attempt to implement the script using FTP for remote copy, I receive the following error.

script did not successfully complete: (can't read "::destination_parameters__pruning_mode": no such variable
while executing
"if { $::destination_parameters__pruning_mode eq "Only Prune iApp-Generated Archives" } {
set pruning_suffix $::destination_par..."
invoked from within
"if { $freq != "Disable" } {
Ensure a default $filename_format is set
if { $::destination_parameters__filenam..." line:44)

I am trying to understand the reason for this error. When I choose the "Select the Filename Format" drop-down, I am selecting an option that does include ${host}. Am using code 11.6.1 HF2 on my box. I saw keithhubb post and resolution but would like to understand the reason for the

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