Does the inheritance interferes with some compiler systems used with opt:root include?

>>>>templates/test.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<opt:extend file="extended1.tpl">
<opt:snippet name="extending">
EXTENDING SNIPPET
</opt:snippet>
</opt:extend>

>>>>templates/extended1.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<opt:root include="included.tpl">
BEGIN
<opt:insert snippet="included" />
<opt:insert snippet="extending" />
END
</opt:root>

>>>>templates/included.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<opt:root>
<opt:snippet name="included">
INCLUDED SNIPPET
</opt:snippet>
</opt:root>

>>>>expected.txt
OUTPUT

>>>>result.txt
BEGIN
INCLUDED SNIPPET
EXTENDING SNIPPET
END