Our developer thought this might be helpful change:
They modified the postRender function from line 74 strapper.php
Old code
$format = $input->getCmd('format', 'html');
if ($format != 'html' || $isCli)
return;
New code
$format = $input->getCmd('format', 'html');
if (empty($format))
$format = 'html';
if ($format != 'html' || $isCli)
return;
That fixed the breaking template for us at least.