In the latest beta, processing
\starttext

Hello world!

\stoptext

 produces many lines of

Synchronize ERROR: unknown node type 12

between the lines

fonts           > 'fallback modern-designsize rm 12pt' is loaded
 and

backend         > xmp > using file
'/Applications/ConTeXt/tex/texmf-context/tex/context/base/lpdf-pdx.xml'

Alan