How to reproduce:
1. Create a new Unity project and import the "MySimpleGraph" Script
2. In the Project window, right-click -> Create -> Graph Toolkit Samples -> Simple Graph -> Open the Graph
3. In the Blackboard, create a new Float variable and expand it
4. Enter "123" into the field
5. Press "Ctrl + Z"/"Command + Z" and observe the results

Expected results: The value in the field is 0
Actual results: The value in the field is 12

Reproducible with: 6000.4.0b7, 6000.5.0a6

Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: No other environment tested

Note: This is inconsistent with all numeric and string fields in the Editor, as well as with string fields in the Graph Toolkit