Notification sounds not working while on a phone call

[Depeche Mark]

When I am on a phone call, I used to get notification sounds from my apps and texts. Now i hear nothing, but i see the notification symbol is there after I hang up. I checked my settings under "call alerts" and "notify during calls" is set to "on" , so I should be hearing notification sounds during a phone call. Does anyone know how to solve this?