Custom Elements: Slider Control breaks if no Placeholder is set

1

I’m trying to create custom userfriendly elements with Slider Controls, that should e.g. only override the default styling if necessary. I noticed that if I don’t set a Placeholder or put in some Placeholder Value like “auto”, the Slider completly breaks. Is this how it is supposed to work or a known bug?

		$this->controls['widthOverride'] = [
			'tab' => 'content',
			'label' => esc_html__('Width Override', 'uf-theme'),
			'type' => 'slider',
			'css' => [
				[
					'property' => '--_callout-w',
				],
			],
			'units' => [
				'rem' => [
					'min' => 15,
					'max' => 34,
					'step' => 1,
				],
			],
			'placeholder' => 'auto',
		];

Best Regards
Suat