Background image not displaying on a nested container.

Hey,
We recently updated a website to 1.5.4 from 1.4.4 and we noticed a container that sits inside a custom block we created using Carbon Fields no longer displays the background image set on the container in the Gutenberg editor.

This issue does not occur on v1.4.4, and only occurs after updating to 1.5.4, we haven’t done any further testing to determine what version this feature breaks on, but we know 1.5.4 has this bug.

This is the block structure Slider > Container (with bg image)

Here is the Carbon Fields code:

Block::make(__('slider', $this->text_domain))
			->set_description('Slider')
			->set_icon('images-alt2')
			->set_mode('edit')
			->set_inner_blocks(true)
			->set_inner_blocks_position('below')
			->set_inner_blocks_template(array(
				array('core/paragraph', array(
					'placeholder' => 'Slider blocks go here',
				)),
			))
			->set_category('custom-blocks', __('Blocks', $this->text_domain))
			->set_render_callback(function ($fields, $attributes, $inner_blocks) {
				$vars['fields'] = $fields;
				$vars['content'] = $inner_blocks;
				$vars['attributes'] = $attributes;
				$vars['index'] = uniqid();
				Timber::render('/blocks/slider.html.twig', $vars);
			});