Email discussion thread: https://lists.ogf.org/archives/list/dfdl-wg@lists.ogf.org/thread/5ET2RPDCHH6OGFGDTGVLYXC2MAK26QAD/
When a facet constraint appears on a simpleType used as a prefixLengthType, this constraint applies to the value of the prefix, not the value of the length computed from that prefix as adjusted by dfdl:prefixIncludesPrefixLength.