In both of the views the variable should have the same value, as the variables are imported.

>>>>templates/test.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!-- Include a file -->
<opt:root>
Foo{$variable}
<opt:include file="included.tpl" import="yes" />
</opt:root>

>>>>templates/included.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!-- Include a file -->
<opt:root>
Bar{$variable}
</opt:root>

>>>>expected.txt
OUTPUT

>>>>result.txt
FooABarA
>>>>data.php
$view->variable = 'A';