The bug was caused by a defect of the patch for the bug 11081.
The patch was actually a port of the fix this bug from the mysql
code line. Later a correction of this fix was added to the
mysql code. Here's the comment this correction was provided with:

  Bug#16499751: Opening cursor on SELECT in stored procedure causes segfault
  This is a regression from the fix of bug#14740889.
  The fix started using another set of expressions as the source for
  the temporary table used for the materialized cursor. However,
  JOIN::make_tmp_tables_info() calls setup_copy_fields() which creates
  an Item_copy wrapper object on top of the function being selected.
  The Item_copy objects were not properly handled by create_tmp_table -
  they were simply ignored. This patch creates temporary table fields
  based on the underlying item of the Item_copy objects.

The test case for the bug 13346 was taken from mdev-13380.