CDATA marker stripped in Memsource custom element

I log here an issue reported from Ocelot users, due to a bug in Okapi. An issue has already been logged to Okapi https://bitbucket.org/okapiframework/okapi/issues/624/xliff-filter-cdata-markup-stripped-in

Attached is a file produced by Memsource. It contains a CDATA markup embedded in a custom <m:open-mark-content> element.
When parsed through the XLIFF Filter, the markup is stripped and the embedded content is written out and the resulting file is invalid (see the "afterXLIFFFilter.xliff" attachment).

As a consequence this file cannot be saved in Ocelot as it is invalid.