OpenXML filter: formatting issues in Arabic translation (RTL)

I use the okf_openxml to prepare a Word file. The translated document has formatting issues (e.g. expected formatting is not there, unexpected formatting is added).

Even if you don't know Arabic, you can see the two issues in the following screenshot:

As you can see in the screenshot, part of the translation is bolded whereas the source is not. I can confirm all tags have been handled correctly in the OmegaT project. I have used the option "Remove leading and trailing tags" (in Project settings > File filters) but I doubt that has any relevance, since I have the same issues if I don't.

Sample OmegaT project and Rainbow settings attached. Thanks in advance.
Let me know if any questions about Arabic.