Screen goes blank in landscape view whenever the phone is locked and unlocked

Expected behavior

At all activities ,I expected the app to still run well when I lock and unlocked the phone while the screen is in landscape view, without displaying a blank screen.

Actual behavior

In any of the Activity in the app, when I rotate to landscape view then lock and unlock my phone again while still at landscape view, the activity goes blank.

How to reproduce

• Download the Voice app from play store
• Launch the app
• At any of the Activity in the app, rotate the screen to landscape
• Lock and unlock the phone, while still keeping the screen in landscape view.
• App shows a blank screen

• Version : Version 3.6.3
• Device : Gionee A1 Lite
• Operating system: Android 7.0

Recording Of The Bug