I tested this, and it seems that with an expression mapping, {value} is not a valid identifier in the expression.
Changing {value} to {view.custom.tempF} in each expression still did not work, which I figured should work. Adding one of the expressions to the fallback value, shows that the first expression is evaluating to true. 
check these threads out for more details
Transform Map Expression Not working properly - Ignition - Inductive Automation Forum
Expression to color/StyleClass map transform example - Ignition - Inductive Automation Forum