Why is it Booting Up Twice?

Hello all,

Recently upgraded the SSD on my Mid 2014 13” Macbook Pro. Bought a 480GB OWC Aura Pro X2 SSD which was pretty easy to install and the only thing I had to do for a successful install was upgrade the OS to High Sierra 10.13.6 for drive compatibility.

I created a final backup with Time Machine, installed the new SSD, reinstalled the OS and everything works just fine, minus two incredibly annoying things started happening.

1. Whenever I boot my Mac, it has to do it twice and it’s quite slow. I press the On button, it chimes once, it backlights to black, apple logo doesn’t appear. Then turns off, it chimes again automatically, backlights to black, long wait then the apple logo appears together with the loading bar and it’s all normal from then onwards.
2. When I close the lid to put it on standby and then reopen it, it very often doesn’t turn on again. It backlights to black, so the laptop is indeed still working but won’t do anything else, so I have to hard-reboot it in order to use it again.

Another weird symptom is that a couple of times I just shut the lid and didn’t reopen it for a few hours, the mac was red hot and the fan was going crazy!

Using certified diagnostic softwares didn’t flag up anything wrong hardware-wise. Tried resetting the PRAM but didn’t do anything to it.

Can anyone please help with any suggestion on what to do?

Many thanks!!