When an xml:id attribute is written to a DOM result tree, Saxon calls setIdAttributeNS passing ":id" as the local name rather than "id".
A patch is being placed in Subversion.
Fixed on both 9.0 and 9.1 branches
Fixed in 9.1.0.3
Fixed on both 9.0 and 9.1 branches
Fixed in 9.1.0.3