Symptoms
If a file name in a checkfile condition contains an environment variable it will not get evaluated using "Does Not Exist" . The environment variable will get evaluated properly if it's part of the path to the file.
Cause
This is a change in behavior from 6.x to 8.0 because the backend stack is in java.
Resolution
Put curly brackets around the environment variable name in the File Name field of the condition. Don't put the curly brackets around the $ sign.
Example: The file Name field contains the following. /home/qa4/ard/$DIST/DRC850.${DIST}.tmp
The $DIST in the path to the file does not need curly brackets around it but the $DIST in the file name does require them to be evaluated.