[4.0 dev] Bugs in field manager

[JoomlaBelarus]

When enable php errors Maximum i see same notes
Above title field

Deprecated: explode(): Passing null to parameter #2 ($string) of type string is deprecated in /home/testsite.org/plugins/fields/radicalmultifield/src/Extension/RadicalMultiField.php on line 313

i change row - $extendfield = explode(',', (string)$this->params->get('extendfield'));

and above Template for category * and Template for item *

Deprecated: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /home/testsite.org/plugins/fields/radicalmultifield/src/Field/PluginlayoutField.php on line 94

I add (string) - no notice
// Get the template.
$template = (string)$this->element['template'];

	$template = preg_replace('#\W#', '',  $template );

	// Get the style.
	$template_style_id = '';
	if ($this->form instanceof Form)
	{
		$template_style_id = (string)$this->form->getValue('template_style_id');
		$template_style_id = preg_replace("#\W#", '', $template_style_id);
	}