Just as a heads up, I noticed today that my Khomo Case wasn’t causing my iPad to wake/sleep. At first I assumed it was a faulty case, but to be sure I checked my settings.
Sure enough, in Settings>Display & Brightness “lock & unlock” with iPad cover had somehow been toggled off. Perhaps my iPad Pro was remaining on every time I closed the cover and thought it was off.
It may be worth checking for others.