DateTimeFormat returns different results in CF2016 and 2018

I am using GetHttpTimeString() function to get the current date and time in UTC/GMT. But when I format it using DateTimeFormat, its returning different results:

In CF2016, when I do this:

<cfdump var="#GetHttpTimeString()#">

<cfdump var="#DateTimeFormat(GetHttpTimeString(), "yyyy-mm-dd HH:nn:ss")#">

it will return:

Tue, 18 Sep 2018 17:44:27 GMT --> UTC

2018-09-18 17:44:27 --> still in UTC

In CF2018, when I do this:

<cfdump var="#GetHttpTimeString()#">

<cfdump var="#DateTimeFormat(GetHttpTimeString(), "yyyy-mm-dd HH:nn:ss")#">

it will return:

Tue, 18 Sep 2018 17:44:27 GMT --> UTC

2018-09-18 12:44:27 --> current date/time in my timezone

Unless I pass a third argument for the timezone, it will use the server's timezone by default.

Is this an intentional change, if it is, I can't find anything in the 2018 Release Notes.

Thank you!

Ollie de Guzman