Current month convert is OK
$fromTz = new \DateTimeZone('UTC');
$toTz = new \DateTimeZone('America/Nipigon');
$carbonUtoA = Carbon\Carbon::createFromFormat('Y-m-d H:i:s', '2020-10-22 17:00:00', $fromTz)->setTimezone($toTz);
echo $carbonUtoA->format('Y-m-d H:i:s'); // 2020-10-22 13:00:00
date_default_timezone_set('UTC');
$dateTime = new DateTime('2020-10-22 17:00:00');
$toTz = new DateTimeZone('America/Nipigon');
$dateTime->setTimezone($toTz);
echo $dateTime->format('Y-m-d H:i:s'); // 2020-10-22 13:00:00
Next month covert is not same as current month
$fromTz = new \DateTimeZone('UTC');
$toTz = new \DateTimeZone('America/Nipigon');
$carbonUtoA = Carbon\Carbon::createFromFormat('Y-m-d H:i:s', '2020-11-22 17:00:00', $fromTz)->setTimezone($toTz);
echo $carbonUtoA->format('Y-m-d H:i:s'); // 2020-11-22 12:00:00
date_default_timezone_set('UTC');
$dateTime = new DateTime('2020-11-22 17:00:00');
$toTz = new DateTimeZone('America/Nipigon');
$dateTime->setTimezone($toTz);
echo $dateTime->format('Y-m-d H:i:s'); // 2020-11-22 12:00:00
But it should be same the time as current month 13:00:00
because before convert in UTC the time was same 17:00:00