Function Packs Do Not Use New Execute Format

When using the "Upcoming Creator Features" option, the new execute format does not get used for functions in behavior packs.

Steps to Reproduce:

1. Create A World With "Upcoming Creator Features Enabled"
2. Create A Basic Behavior Pack With A Function. This Function Should Use Any Execute Command (New Format)
3. Attempt To Load Pack In Game

Observed Results:

Error Is Thrown And Function Is Not Used

Expected Results:

Pack Should Use New Execute Format

Screenshots/Videos:

 

The Pack Has Been Attached To The Report.