zwnj character (unicode) will be omitted in "Text variable" and export to epub

Hello

In Farsi-persian writing zwnj character (unicode) is vital. (https://en.wikipedia.org/wiki/Zero-width_non-joiner). unfortunately If I use text variable like "running header" this character will be omited. 

It will happen in any version of indesign however I use middle eastren version. zwnj is sessential character in persian and it is not possible to use another character (It os not optional It is mandatory). meanwhile If I export it to epub it will be omitted as well.

and if I copy text with zwnj like (می‌خانه) and copy it on "numbering and section options it will be omitted as well.

Thanks.