Help Blue Horizontal Line Moving Up & Down

[beingmeraki]

Hey all,
Kindly need your advice on my Samsung Note 8 devices.
I got a problem when my phone was locked. There was a blue horizontal bar kept moving up and down meanwhile my home screen was freeze. I couldn't enter my pin and I couldn't answer a phone call either. Could you please help me identify what is happening with my devices?

Thank you

Best Regards

 

[marctronixx]

smoke this over. maybe something in accessibility settings...

you can also try this:

For galaxy s8 its volume up and power keys