EL Comparison don't works in attributes

I have a class with BigDecimal attribute:

public class Foo {
    private BigDecimal value;
}

This code works fine

<p>${foo.value lt 0}</p>

And this code too:

<p>${foo.value lt 0 ? 'negative' : 'positive'}</p>

But when I use the expression in the attribute, I get the errot bellow:

<p class="${foo.value lt 0 ? 'negative' : 'positive'}">text</p>

The class 'Foo' does not have the property 'valuelt0'.