Error on installation of RTFM Site skeleton / learn2

Am I the only one who sees an error on a fresh setup of the current skeleton of RTFM Site/learn 2?

Server Error
Sorry, something went terribly wrong!
0 - An exception has been thrown during the rendering of a template (“A non-numeric value encountered”).
For further details please review your logs/ folder, or enable displaying of errors in your system configuration

Windows 10 x64
PHP 7.1.1

[2017-01-30 14:56:29] grav.CRITICAL: An exception has been thrown during the rendering of a template (“A non-numeric value encountered”). - Trace: #0 R:\php_grav\faq.bullion-investor.com\vendor wig wig\lib\Twig\Templat e.php(403): Twig_Template->displayWithErrorHandling(Array, Array) #1 D: est\demo.rtfm.com\cache wig\62\624d6b3f4a128a2aeb0cfefba3ad49fe5f 4bce7c0e1aa1a8e54c184b61414155.php(210): Twig_Template->display(Array) #2 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(215): __TwigTemplate_d2e0d92462f391a562d0d10b2beb05063742dede4aefd70e1442112 3a635f18e->block_sidebar(Array, Array) #3 D: est\demo.rtfm.com\cache wig\62\624d6b3f4a128a2aeb0cfefba3ad49fe5f 4bce 7c0e1aa1a8e54c184b61414155.php(50): Twig_Template->displayBlock(‘sidebar’, Array, Array) #4 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(432): __TwigTemplate_d2e0d92462f391a562d0d10b2beb05063742dede4aefd70e1442112 3a635f18e->doDisplay(Array, Array) #5 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(403): Twig_Template->displayWithErrorHandling(Array, Array) #6 D: est\demo.rtfm.com\cache wig\a9\a947c07ede3289fcebcee93ced3381cc88 105d042ad3ddc91898db5a301675d3.php(36): Twig_Template->display(Array, Array) #7 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(432): __TwigTemplate_1bf39ee7b869327dd402771117466a455f272378721915bd802dfeb 1d29c796e->doDisplay(Array, Array) #8 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(403): Twig_Template->displayWithErrorHandling(Array, Array) #9 D: est\demo.rtfm.com\cache wig\d5\d5cfa4b61051a1915b62ce2cedbe83b4c9 2ec6f717a8fab1e64892018a1114a0.php(24): Twig_Template->display(Array, Array) #10 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(432): __TwigTemplate_59a1956f1420698c7c3f6be7dbc87239c3adebd282bda30bc0c18c7 46badb8d6->doDisplay(Array, Array) #11 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(403): Twig_Template->displayWithErrorHandling(Array, Array) #12 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Template.php(411): Twig_Template->display(Array) #13 D: est\demo.rtfm.com\vendor wig wig\lib\Twig\Environment.php(362): Twig_Template->render(Array) #14 D: est\demo.rtfm.com\system\src\Grav\Common\Twig\Twig.php(348): Twig_Environment->render(‘chapter.html.tw…’, Array) #15 D: est\demo.rtfm.com\system\src\Grav\Common\Service\OutputServiceProv ider.php(18): Grav\Common\Twig\Twig->processSite(‘html’) #16 D: est\demo.rtfm.com\vendor\pimple\pimple\src\Pimple\Container.php(11 3): Grav\Common\Service\OutputServiceProvider->Grav\Common\Service{closur e}(Object(Grav\Common\Grav)) #17 D: est\demo.rtfm.com\system\src\Grav\Common\Processors\RenderProcesso r.php(17): Pimple\Container->offsetGet(‘output’) #18 D: est\demo.rtfm.com\system\src\Grav\Common\Grav.php(122): Grav\Common\Processors\RenderProcessor->process() #19 D: est\demo.rtfm.com\system\src\Grav\Common\Grav.php(364): Grav\Common\Grav->Grav\Common{closure}() #20 [internal function]: Grav\Common\Grav::Grav\Common{closure}(‘render’, ‘Render’, Object(Closure)) #21 D: est\demo.rtfm.com\system\src\Grav\Common\Grav.php(340): call_user_func_array(Object(Closure), Array) #22 D: est\demo.rtfm.com\system\src\Grav\Common\Grav.php(123): Grav\Common\Grav->__call(‘measureTime’, Array) #23 D: est\demo.rtfm.com\index.php(51): Grav\Common\Grav->process() #24 {main} [] []

Seems like a PHP 7.1 issue, does not happen on 7.0 - looking at it now.

The problem is in the theme. In this file https://github.com/getgrav/grav-theme-learn2/blob/develop/templates/partials/sidebar.html.twig#L17 change the highlighted line to {{ _self.loop(p, parent_loop|default(0)+loop.index) }}

Does that fix it?

Fantastic, it works!
Thanks a lot.