HP Ubuntu 16.04 - Airplane mode hardblocks on when laptop sleeps/closes

[prykor]

I have a HP Pavilion Notebook.

I recently installed Ubuntu 16.04 and have been having issues with airplane mode turning on and not being able to be reversed.

When my laptop first boots, wifi works fine and I can switch airplane mode on/off. (F12 on my machine is airplane mode instead of wifi)
However, as soon as the laptop closes/sleeps, airplane mode turns on and cannot be turned off through either F12 or the network screen.

sudo rfkill list all

returns wifi - softblocked: no, hardblocked: yes
I have tried

sudo rfkill unblock all

but it does not work.

How can I stop airplane mode turning on when the laptop sleeps? And what might be causing this?