Found the answer after some further investigation.
[I]f the first two characters of the name are both upper case and if so leave it alone.
Section 8.8 of the JavaBean Spec by Sun states:
8.8 Capitalization of inferred names.
When we use design patterns to infer a property or event name, we need
to decide what rules to follow for capitalizing the inferred name. If
we extract the name from the middle of a normal mixedCase style Java
name then the name will, by default, begin with a capital letter.
Java programmers are accustomed to having normal identifiers start
with lower case letters. Vigorous reviewer input has convinced us that
we should follow this same conventional rule for property and event
Thus when we extract a property or event name from the middle of an
existing Java name, we normally convert the first character to lower
case. However to support the occasional use of all upper-case names,
we check if the first two characters of the name are both upper case
and if so leave it alone. So for example,
"FooBah" becomes "fooBah"
"Z" becomes "z"
"URL" becomes "URL"
We provide a method Introspector.decapitalize which implements this
JavaBeans Introspection -- Sun Microsystems -- 10/12/97