Email Attachments sent as UTF-16LE instead of UTF-8

Until now we've been sending emails with text attachments using cl_document_bcs. These files were, and need to be UTF-8 for our recipient.

Since Enhancement Pack 6 SAP now sends them as UTF-16LE (see sost.png). How can we change this?

Changing the settings in SCOT to UTF-8 does not help (see scot.png).

cl_document_bcs=>create_document( ... ).

...

lo_document->add_attachment( i_att_content_text = ... ).