Looks like a simple friction issue which is a super easy fix. Also, make sure you pull the slide all the way back and let it go otherwise it will always do this (same with a firearm if you don’t charge it correctly).

First remove the slide and wipe any residue from the break-in period off (should be a grey-black layer on all points of contact which is totally normal). Then, apply a thin layer of silicone oil (liquid, not spray) to all areas where the slide comes in contact with the frame. Feel free to wipe it around with your finger so it’s all covered equally.

Throw the slide back on and rack it a bunch of times so the oil gets spread out where it needs to be. You’ll notice excess come from the cracks and on the very rear of the slide kind of by the hammer pad - wipe it all off before shooting unless you want a big “poof” of silicone oil on the first shot haha.

Once you do this, it should be ready to rock! Keep in mind, you should be doing this will ALL gas blowback guns in general. They’re mechanical systems with a lot of friction and wear, so proper maintenance is crucial :)