The new OS Mojave is weird

I just found this today.
So when we hit space on multiple images, usually it will show the preview and it will start from the top or number one on the list but today, I just found out that when you selected multiple images using your mouse, tablet or trackpad and hit space, the preview will not show from the top or number one but it was from the bottom of the list and what even weirder is that when I hit next button or ( -> ) on my keyboard, usually when you hit next from the bottom file back to the first file, but in my case it was like this, I have three Images selected using mouse, so when I hit space, it will show number three instead of number one and I hit next button instead of going to number one as normal thing to do, the preview will go to number two and number one. Everything is reversed.

Is this suppose to be like this? because the last OS is not like this.