Section 31.2, 31.3, 31.4 specify dfdl:escapeEscapeCharacter="%"
This needs to be "%%".
Or needs to be changed to use english prose to say the dfdl:escapeEscapeCharacter is '%' (requires property to be defined as dfdl:escapeEscapeCharacter="%%" since % are used for character entities syntax in DFDL string literals).
Or perhaps better would be to change the usage of % in these examples to use $ or other neutral character to avoid the confusion.