Hi @nurjan14, apologies for the delay on responding to this.
We’ve had some issues with flickering lumen lights in the past, which if I remember correctly were caused by a faulty Pixhawk servo output chip giving incorrect timings. I would recommend you contact support@bluerobotics.com to confirm the issue and sort out a relevant replacement or refund 
The Vectored_6DOF frame is the “Heavy” frame, although it should be showing up with an image when connected to ArduSub (similar to this). I would recommend confirming that your software versions match our latest recommendations, then try setting the heavy frame, resetting parameters, and seeing if thing are improved. If the issue is still present then contacting the support email is your best bet