Blackboard Key Values Persisting Between PIE Sessions

Values set on Blackboard Keys are persisting after stopping and starting a new PIE session. Restarting the editor sets these values back to NULL.

1. Open the attached project
2. PIE
3. Check the output log (Previous Key Value should be Null, and New Key Value should be TEST
4. Exit PIE and PIE a second time
5. Check the output log

Result: Previous Key Value is TEST

Expected: Previous Key Value would be null.