Alcatel Idol 4 - Two contacts are muted although it says notification says it is on.

[AC Question]

I just noticed teo of my contacts in my sms list have a bell with a line going through it typw of icon beside it. I am not getting any notifications from with of them. I checked the settings on the top right when in their thread and it says the notifications are on. I turned it off and then back on, but the muted bell is still there and no sound for those two contacts only. One is my son. Help!! Thank you