Pegasus Ohms Jumping Around

Hi all,

My Pegasus just arrived in the post this morning. I fitted it with a brand new Nitecore 2000mAh 18650 flat-top battery then charged it so the battery is full.
I'm using a Cartel Cascata RDA which is absolutely fine on other devices.

The Pegasus ohms are jumping around quite a bit. And when fired, the battery drops considerably (on the display). I'm not even sure if this is safe.
I built another coil for this RDA just in case. No difference. I tried the solutions at the top of the page too. No difference. It's kanthal wire.

I've also tried with a brand new LG 18650 2500mAh battery. Same thing happens.

I've posted a (rubbish) video to YouTube to explain what I'm on about, which can be found here:

My face isn't much to look at, but I'd like to keep it in one piece. Is this safe? Should I be doing something differently?
I had a similar issue with an MVP 3.0, but that developed over months and I eventually just wrote it off.

I love the look and feel of this mod. I don't want to have to send it back.

Thanks.