1909 Upgrade Fixlet Fails in Action Script

When attempting to upgrade systems in our environment with the Windows 10 Business Editions Version 1909 Available - Windows 10 (x64) (English (United States)) fixlet (ID 1111414), we encounter the following failure in the Action Script: Failed continue if {exists file (parameter “workISO”)}. All previous lines of the Action Script complete successfully.

The 1909 upgrade fixlet is failing here:
Completed parameter “workISO” = "{pathname of client folder of current site & “__Download\en_windows_10_business_editions_version_1909_updated_oct_2020_x64_dvd_3cfd51ef.iso”}"
Failed continue if {exists file (parameter “workISO”)}

From the logs of the failed computers:
Command succeeded parameter “workISO” = “C:\Program Files (x86)\BigFix Enterprise\BES Client__BESData\actionsite__Download\en_windows_10_business_editions_version_1909_updated_oct_2020_x64_dvd_3cfd51ef.iso” (action:27947)
Command succeeded (evaluated false) continue if {exists file (parameter “workISO”)} (action:27947)

I have confirmed that the ISO downloaded successfully and exists at this location on failed computers:
C:\Program Files (x86)\BigFix Enterprise\BES Client__BESData\actionsite__Download\en_windows_10_business_editions_version_1909_updated_oct_2020_x64_dvd_3cfd51ef.iso

I have confirmed that the Action Script of the 1909 upgrade fixlet is identical to the 1903 upgrade fixlet, which has been working for us. Also, I have tried removing “continue if {exists file (parameter “workISO”)}” from the 1909 Action Script, but the results are the same.

Any ideas or suggestions on how to resolve this issue would be greatly appreciated.

Thank you,
MXG