Det problemet har jag upplevt vid inkommande whatsapp samtal.
Använder du någon tredje app till dialern?
Här finns en möjlig lösning jag hitta vid en snabb googling. Hoppas det hjälper
Solved: Note 8, not showing incoming calls screen when the... - Samsung Community - 194083
Tydligen så ska detta fixa problemet:
I have figured out how to fix this after 3 weeks of dealing with it.
Step 1: call youself
Step 2: swipe down on notification bar to view the call(usually how you would answer while dealing with this issue)
Step 3: swipe the call to the right and click the setting wheel.
Step 4: select "do not hide notifications"
Step 5: test call after doing this with the screen off, its should work.
Click to expand...