screen going black whenever front camera covered

I was having the same issue after installing ios 11.4.1 update on the iphone 6s+ (with the screen going black whenever the front ‘selfie’ camera was covered inadvertently). This was especially frustrating when attempting to edit text in the browser’s address bar; or to edit the name of any bookmarks folder, etc. After reading here about the “hard reset fix” (simultaneously holding down the power and home buttons, for the 6s+), I tried it too; and the problem was resolved and hasn’t so far recurred.