Yes, I can confirm this behavior.
I do not know why VFP assumes Size property as Currency data type. But behavior for changing Size to value, other than you specify, is something internal for StdFont class. Try the following (I do this in VB): put TreeView ActiveX Control on the form and open it's Property Pages. From Font page change font size to 8. When you press Apply button, size is changed to 8.25.
All Font properties of all ActiveX controls uses StdFont object...