Enrico Zimuel as a new post to his blog today talking about his exploration of a Zend Framework bug related to the JSON handling of the Zend_Json component. The issue was related to the conversion of XML to JSON but it only happened in specific instances.
As you can see the bar value, of the a element [in the example code], is not represented in JSON. This issue comes also with other XML documents, and in general when an XML node has a single character data child, any attributes are lost.
In tracking down the issue, he followed a lead through a possible SimpleXML issue and, with some further testing, found a simple, non-Zend Framework script to behave the same way. It dropped the "bar" value of the example XML from the object's return value. To get around this bug, he created a new conversion algorithm that redefined the _processXML method in Zend_Json to work with the Zend_Json_Expr functionality to parse things more correctly. If you can't wait for the next release to get it into your codebase, you can grab the code from his post.