Function #'create-template-printer has :external-format key parameter which is used when opening a file with a template to be filled.

But if that file <tmpl_include>s some other file, than :external-format supplied is not used when opening the second file as it should be.

In #'create-template-printer-aux function #'create-template-printer function is called with an included file only. May be it is worth to make a special variable like *hunchentoot-default-external-format* for default value of :external-format parameter for #'create-template-printer function.

In SBCL special variable sb-impl::*default-external-format* can be binded to an external-format required as a workaround.

-- Registered Linux User #124759