Pdf2Dom is a PDF parser that converts the documents to a HTML DOM representation. The obtained DOM tree may be then serialized to a HTML file or further processed. A command-line utility for converting the PDF documents to HTML is included in the distribution package. Pdf2Dom may be also used as an independent Java library with a standard DOM interface for your DOM-based applications or as an alternative parser for the CSSBox rendering engine in order to add the PDF processing capability to CSSBox. Pdf2Dom is based on the Apache PDFBox™ library.
This is not a bug. Development version available in the git repo may depend on development versions of other libraries (snapshots). They are resolved just before a new release. You may obtain current cssbox from the git as well (git clone and mvn install) or use the solution you mention if it works for you.
Resolution: Modify pom to install cssbox 4.14 instead.