Error when adding a post to a series

Hi there,

my latest post cannot be added to an existing series of articles. I receive the following error / warning message:

Warning: A non-numeric value encountered in /<path_to_wordpress/wp-content/plugins/organize-series/orgSeries-template-tags.php on line 451

But when I look into the file, there is no non-numeric value in line 451 or I misunderstood something:

<line 446>

	foreach ($posts_in_series as $seriespost) {
		$custom_next = esc_html(token_replace($settings['series_nextpost_nav_custom_text'], 'other', $seriespost['id'], $series_ID));
		$custom_prev = esc_html(token_replace($settings['series_prevpost_nav_custom_text'], 'other', $seriespost['id'], $series_ID))  ;
		if ($next) {
			if ( ($seriespost['part'] - $cur_part) == 1) {
					if ( !empty($custom_next) ) $title = $custom_next;
					else $title = get_the_title($seriespost['id']);
					$link = get_permalink($seriespost['id']);
					$result .= '<a href="' . $link . '" title="' . $title . '">' . $title . '</a>';
					}
		}

<line 456>

Nothing was changed before. The only way to publish an article is to do it without adding it to a series. My latest article will not be part of a series although it should. Can you give any advice what to do?

Cheers, Henning

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