ANIMATE negative value creates a new Custom attribute

[Wainiha]

Using a negative value for ANIMATE in an 'onClick' behavior creates a new Custom attribute - SU Pro 7.1 - image shows example:

1. animate(doorAngle,0,90) works correctly.

2. Interact clicks toggle values between "0" and "90", doors open/close as expected.

3. Change animate value from "90" to "-90" and click to Interact; 'doorAngle' value changes to "-90" and doors open backwards as expected.

4. Click again and ERROR! Instead of 'doorAngle' value changing from "-90" back to "0" as expected (closing the doors), a new Custom attribute is created with the name "-90", and on subsequent Interact clicks, its value toggles instead of 'doorAngle'.