Empty Value in Custom Field from Multiple Record Fieldset causes WSOD in Views

In a custom fieldset which holds multiple values, if one of the individual fields is empty for one of the records (ie has not had a value entered), when this field is displayed in a view this causes a WSOD if the multiple values setting to display all values in the same row is not ticked for this field in the view. The error is:

Error: Unsupported operand types in Drupal\views\Plugin\views\field\FieldPluginBase->advancedRender() (line 1177 of /var/www/vhosts/xxx/xxx/dir/html/core/modules/views/src/Plugin/views/field/FieldPluginBase.php)

This may be related to this issue → .

Maybe, there just needs to be a check for empty values?