PHP Carbon Issue modify time on Daylight Saving Time (DST) - php

Question

I have issue with Carbon liblary on PHP when modify the day (end day light saving) at UK timezone,
I'm using Carbon version: 1.31.0, PHP version: 5.6.11 on Laravel 5.5
this is my function convert to startOfHour:
public function getStartHour($timestamp)
{
$carbonDate = Carbon::createFromTimestamp($timestamp, 'Europe/London');
$startHour = $carbonDate->startOfHour()->timestamp;
return $startHour;
}
// Case 1:
// Sunday October 27, 2019 00:00:00 (am) GMT
// Sunday October 27, 2019 01:00:00 (am) (Timezone + 1 , On daylight saving)
$time = $this->getStartHour(1572134400); // 1572138000 (Issue here)
//My expected: 1572134400
// Case 2:
// Sunday October 27, 2019 00:30:00 (am) GMT
// Sunday October 27, 2019 01:30:00 (am) (Timezone + 1 , On daylight saving)
$time = $this->getStartHour(1572136200); // 1572138000 (Issue here)
//My expected: 1572134400
// Case 3:
// Sunday October 27, 2019 01:00:00 (am) UCT
// Sunday October 27, 2019 01:00:00 (am) UK (Timezone + 0)
$time = $this->getStartHour(1572138000); // 1572138000 - 01:00:00 (Ok)
// Case 4:
// Sunday October 27, 2019 01:30:00 (am) UTC
// Sunday October 27, 2019 01:00:00 (am) (Timezone + 0)
$time = $this->getStartHour(1572139800); // 1572138000 - 10:00:00 (Ok)
4 case these return same result (1572138000). It not right on the real case.
But when I use MomentJs library it converts right my expected
Here is my Js code with Moment
function getStartHour (timestamp) {
const m = moment(timestamp * 1000).tz('Europe/London');
startHour = m.clone().startOf('hour').unix()
return startHour;
}
What is different on 2 library and how can I fix PHP code return same JS code.
Thank you very much.