message preview pane is stuck on lock screen and will not go away

Hi All! Just wanted to let you know I chatted with tech support about this problem and here is what fixed it on my phone.

Please go to settings>general>reset> reset all settings

Try a forced restart. To force restart your device, press and hold both the Sleep/Wake and Home buttons for at least ten seconds, until you see the Apple logo.

After the phone starts up, force close the messages app and see if that fixes it.

The manner in which you force restart depends on that model of phone you have.

• On an iPhone 8 or iPhone 8 Plus: Press and quickly release the Volume Up button. Then press and quickly release the Volume Down button. Finally, press and hold the Side button until you see the Apple logo.
• On an iPhone 7 or iPhone 7 Plus: Press and hold both the Side and Volume Down buttons for at least 10 seconds, until you see the Apple logo.
• On an iPhone 6s and earlier, iPad, or iPod touch: Press and hold both the Home and the Top (or Side) buttons for at least 10 seconds, until you see the Apple logo.

I have this exact same problem on my iPhone 6s.

It started after the update to iOS11, and has persisted through the next 2 updates (to 11.0.2).

The problem corrects after a forced restart, but eventually after a few hours or a couple of messages, the problem returns.

Sometimes, the screen turns on when it's in my pocket and displays a blank message preview, which is wasting the battery.

Another issue seems to be the constant looking for telephone signal if I'm in an area of bad reception which is draining the battery life very quickly (didn't happen in iOS 10).

This problem does not occur on my wife's 6, which has the same updates.

Phone won’t do a forced restart when I hold the button for 10secs

Forced restart only fixes the problem until another text message is received and then the problem is there again. Please advise another step.