Horizontal flickering lines on Agilent U1602B, please advice

[kamcm]

The LCD screen of U1602B keeps flickering and caused eye strain.

How to reproduce?

Warm-up the U1602B for 15 minutes and the Horizontal flickering lines will getting worse in default contrast setting.
By the way, set the contrast to 76 will make the flickering more obvious.
Anyone have the same problem?

Is it an individual case or a broader problem?

Please advise,

Thanks

http://youtu.be/QBML3cBM3mE

[kamcm]

Anyone have the same instrument and able to confirm it with me ?

Is it irregular?

Thanks!