Apparent Traffic Graph bug (Fatal error)

Spacecase

Here's the PHP_errors log:

[10-Sep-2023 15:04:22 America/New_York] PHP Fatal error:  Uncaught TypeError: format_number(): Argument #1 ($num) must be of type int, string given, called in /usr/local/pfSense/include/www/bandwidth_by_ip.inc on line 172 and defined in /etc/inc/util.inc:2206
Stack trace:
#0 /usr/local/pfSense/include/www/bandwidth_by_ip.inc(172): format_number('', 2)
#1 /usr/local/www/bandwidth_by_ip.php(36): printBandwidth('wan', 'local', 'in', 'hostname', 'iftop')
#2 {main}
  thrown in /etc/inc/util.inc on line 2206
[10-Sep-2023 15:04:25 America/New_York] PHP Fatal error:  Uncaught TypeError: format_number(): Argument #1 ($num) must be of type int, string given, called in /usr/local/pfSense/include/www/bandwidth_by_ip.inc on line 172 and defined in /etc/inc/util.inc:2206
Stack trace:
#0 /usr/local/pfSense/include/www/bandwidth_by_ip.inc(172): format_number('', 2)
#1 /usr/local/www/bandwidth_by_ip.php(36): printBandwidth('wan', 'local', 'in', 'hostname', 'iftop')
#2 {main}
  thrown in /etc/inc/util.inc on line 2206

Here's the configuration:

I'm running pfSense CE 2.7.0-RELEASE on a Netgate MBT-4220.

I've searched Redmine and this forum and the error looks unique.