Try the following code:
trace(2+2==4)
It will return always nil instead of true/false which makes trace() useless for debugging conditions. It will return nil in the case that conditional would result in false as well such as this: trace(3-3==math.sqrt(math.pi))
Use the function tostring:
trace(tostring(2+2==4))
But yes, it could be a regular behavior of the trace function same as in the standard lua print function.
trace(tostring(2+2==4))
Ahh, @Crutiatix beat me to it.
^
added tostring behavior to print/font/trace api
done in .27