Program crashes horribly, and I'm not doing anything illegal

The following program results in a short dump, for now I've chalked it up to a bug with the ABAP compiler/run-time. Various other permutation upon the same theme runs fine... just this particular combination of dynamic class and returning a char1 to an exporting any seems to crash. (a char2 works fine, leading me to suspect UTF-16 handing bugs too)

The resulting short dump message: Access to string reference with destroyed content (it occurs on the final WRITE statement.)

To be clear I understand the error message, I just don't see how it is happening that my reference can possibly be pointing to destroyed content.

Also we have a up-to-date development system with all relevant SAPNOTES applied.

REPORT  z_error_test.
*----------------------------------------------------------------------*
CLASS cl_test DEFINITION.
  PUBLIC SECTION.
    METHODS method_true RETURNING value(r_val) TYPE char1.
    METHODS execute EXPORTING e_result TYPE any.
ENDCLASS.
*
CLASS cl_test IMPLEMENTATION.
  METHOD method_true.
    r_val = 'X'.
  ENDMETHOD.
  METHOD execute.
    e_result = method_true( ).
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  DATA: lcl_test  TYPE REF TO cl_test,
        l_result  TYPE string.

  CREATE OBJECT lcl_test.
  lcl_test->execute( IMPORTING e_result = l_result ).
  WRITE :/ l_result.