ADF Faces RC: Resolving "'BracketSuffix' returned null"

javax.el.PropertyNotFoundException: Target Unreachable, 'BracketSuffix' returned null
 at com.sun.el.parser.AstValue.getTarget(AstValue.java:96)
 at com.sun.el.parser.AstValue.getType(AstValue.java:56)

This is my story:
I have a string status attribute which is represented by a single character in the database but should be displayed in my pages as meaningful words as follows:

• A -Active
• P -Pending
• U -Undefined
• N -New

So I created a Constants class with a map attribute that holds the appropriate key-value pairs and defined this class as an application scoped managed bean.
I refer this in the page as follows:

<af:panelLabelAndMessage label="#{bindings.status.hints.label}"
                                     id="plam1">
  <af:outputText value="#{nisConstants.statusMap[bindings.status.inputValue]}" id="ot1"
                             clientComponent="true"/>                       
</af:panelLabelAndMessage>

And then I started encountering the error above. This is pretty hard to identify if you have a lot of expression in the page that has brackets, and I hope that the ADF Development team will improve on defining the error by including in the trace the expression that causes the problem.

Below is my analysis:

I easily avoided such error by initializing my status attribute to some default value like below:

    private String status = "N";

Cheers!