PHP Runtime Deprecation Notice: Automatic conversion of false to array is deprecated

[bavarianbytes]

Describe the bug
If PHP warnings are active, the frontend throws a 503 error with this message on a page with the PM plugin:

PHP Runtime Deprecation Notice: Automatic conversion of false to array is deprecated in /Users/foobar/typo3conf/ext/pxa_product_manager/Classes/ViewHelpers/RenderMultipleViewHelper.php line 81

To Reproduce
Steps to reproduce the behavior:

1. Set: $GLOBALS['TYPO3_CONF_VARS']['SYS']['displayErrors'] = 1; $GLOBALS['TYPO3_CONF_VARS']['SYS']['exceptionalErrors'] = 12290; in LocalConfiguration.php
2. Click on a page with a plugin CE
3. See error

Additional context
pxa_product_manager version: latest out of TER (11.0.9)