Unable to evaluate an Automation "_ACTIVITY_RESULT" variable (4227761)

When executing a "copy file" activity, and it fails, the value of its "#_ACTIVITY_RESULT#" variable has the PATH of the file it tried to copy, like this:

Copy_1 - Could not find file "\\\\remote_folder\\subfolder_1\\subfolder_n\\example_file.txt".; Inner exception: This file was not available at runtime. The location and user authentication may be different at runtime.

So:

1. - That value won't be useful in a IF activity, at least not until QAT-12485 is resolved.

2. - When trying to use "Substr('#_ACTIVITY_RESULT#', 0, 9)" in a "Set Variable" activity, to save into another variable the part that did not include the PATH, in order to use the OTHER Variable in the IF statement, then TDP's showing this error:

Set_Variable_1 - Object reference not set to an instance of an object.

Object reference not set to an instance of an object.

Failed

And, as one is also unable to use the Substr(...) function to extract just the part that does not include the PATH, then one is unable to evaluate an Automation "_ACTIVITY_RESULT" variable.