After a little googling it turns out that executing:
'rm /tmp/.X0-lock'
solves the problem. Now the output is :
[20:04][claudiu:/>~]$ sudo kate /etc/bluetooth/hcid.conf
QObject::disconnect: Unexpected null parameter
[20:04][claudiu:/>~]$
So there is no need to reopen this bug.
After a little googling it turns out that executing: [claudiu: />~]$ sudo kate /etc/bluetooth/ hcid.conf :disconnect: Unexpected null parameter [claudiu: />~]$
'rm /tmp/.X0-lock'
solves the problem. Now the output is :
[20:04]
QObject:
[20:04]
So there is no need to reopen this bug.