Filters are not always showing on Woocommerce page

Hi,

I’m enjoying your plugin on our website. We run charity sporting-events and also sell some merchandise to raise extra money.

Unfortunately the filters don’t always show on the shop page. This is all the HTML that is generated:

<div id="yith-woocommerce-ajax-navigation-filters-2" class="single-sidebar-box"><div class=" widget_yith-woocommerce-ajax-navigation-filters"></div></div>

If I log in (as admin) and revisit the page, everything shows perfectly fine.

<div id="yith-woocommerce-ajax-navigation-filters-2" class="single-sidebar-box"><div class=" widget_yith-woocommerce-ajax-navigation-filters">
	<div class="yith-wcan-filters no-title enhanced" id="preset_29126" data-preset-id="29126" data-target="">
		<div class="filters-container">
			<form method="POST">
<div class="yith-wcan-filter filter-tax hierarchical text-design" id="filter_29126_0" data-filter-type="tax" data-filter-id="0" data-taxonomy="product_cat" data-multiple="yes" data-relation="or">
etc........

We use your plugin and also use WP-Rocket, Autoptimize en Asset Cleanup (we also use other plugins, but I don’t think they are the cause). We also use Varnish on server-level. If I empty the Varnish cache the filters are back. But after roughly 20 hours orso they dissapear again.

I am not sure wether it has to do with WP-Rocket or with Varnish. Because WP-Rocket should filter out anything that has to do with Woocommerce (that’s what they say). In the Varnish config we also excluded the Woocommerce page where the filters are used.

Maybe I need to exclude something else? Perhaps you have some experience with WP-Rocket or Varnish. We also use Varnish and WP-Rocket with your plugin on another E-commerce website, and we never had any problem there. We tried to copy the settings, but that didn’t help either. We must overlook something.

Btw. we have tried to disable other plugins, and we have tried to empty caches from the mentioned plugins. But the only ones that seem to have any effect (although not always in the same way… :-S ) are WP-Rocket and Varnish.

p.s. if you visit the page there is a chance that you see the filters. Because of the above, we need to check a few times a day. When we see they have dissapeared again, we quickly empty the caches.

The page I need help with: [log in to see the link]