Unescaped closing angle bracket in ITS-excluded target content

Background

The bug happens while using the XML filter together with ITS filter properties.

My content has some phrases and terms in angle brackets, e.g. <foo>. These expressions are encoded as <foo> in the source XML file.

The closing character becomes unescaped in nodes excluded by ITS's locale filter, which breaks the application consuming the translation.

Preconditions

Source file has:

<label key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6" its:localeFilterList="en-PH" its:localeFilterType="exclude">
    <text>&lt;I don’t know&gt;</text>
</label>
<label key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6" its:localeFilterList="en-PH" its:localeFilterType="include">
    <text>&lt;I don’t know&gt;</text>
</label>

Expected result

Translation into en-PH produces this target file:

<label its:localeFilterList="en-PH" its:localeFilterType="exclude" key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6">
    <text>&lt;I don’t know&gt;</text>
</label>
<label its:localeFilterList="en-PH" its:localeFilterType="include" key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6">
    <text>&lt;Je ne sais pas&gt;</text>
</label>

Actual results

Translation into en-PH produces this target file:

<label its:localeFilterList="en-PH" its:localeFilterType="exclude" key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6">
    <text>&lt;I don’t know></text>
</label>
<label its:localeFilterList="en-PH" its:localeFilterType="include" key="ST801KAZ_ST801Q0104KAZ_54c6c210509bc38e7b8bea748938937e_6">
    <text>&lt;Je ne sais pas&gt;</text>
</label>

Comments

I know that there is a flag in the FPRM file for escaping or not escaping the > char. The problem seems to be that this option only works for included nodes, that's the problem: notice the difference depending on whether the label is excluded or included for the target language of the project (which is en-PH).

I got this issue while using the XML filter in OmegaT via the filter plugin, but I could reproduce it if I create an XLIFF file with Rainbow (also attached), which is why I’m reporting the issue in the okapi general tracker and not in the omegat-plugin tracker.

For your convenience, I'm attaching:

the source file (STQ.xml)
the target file
the filter parameters file
the OmegaT package including all of the above
the target XLIFF file

Other bugs that hamper testing

I could not create an OmegaT project in Rainbow 1.45 when doing Utilities > Translation Kit Creation. I selected the OmegaT Project, but the outcome is Generic XLIFF (but this is a different bug).