Property:Has processing error
From Book Owners Online
"Has processing error" is a predefined property provided by Semantic MediaWiki and represents errors that appeared in connection with improper value annotations or input processing. Errors are collected in a container that may include a reference to the property that caused the discrepancy. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.