ClassCastException in SetMatrix() operator processor

java.lang.ClassCastException: org.apache.pdfbox.cos.COSName cannot be cast to org.apache.pdfbox.cos.COSNumber
	at org.apache.pdfbox.contentstream.operator.state.SetMatrix.process(SetMatrix.java:45)
	at org.apache.pdfbox.contentstream.PDFStreamEngine.processOperator(PDFStreamEngine.java:853)
	at org.apache.pdfbox.contentstream.PDFStreamEngine.processStreamOperators(PDFStreamEngine.java:509)
	at org.apache.pdfbox.contentstream.PDFStreamEngine.processStream(PDFStreamEngine.java:477)
	at org.apache.pdfbox.contentstream.PDFStreamEngine.processPage(PDFStreamEngine.java:158)
	at org.apache.pdfbox.rendering.PageDrawer.drawPage(PageDrawer.java:223)