Can I get some help with some message notification problems on my Samsung Galaxy S4 since Lollipop?

[AC Question]

message notification prblems on Samsung Galaxy S4 since Lollipop

Since the Lollipop 5 upgrade, my message notification blue light nor sound chime 8% of my contacts (who live within 4 miles) do not notify me a message is waiting. I only know if I happen unlock the phone and actively LOOK. For the other 92% of contacts, the messages come thru fine. This has caused some ugly misunderstandings.....

Samsung Galaxy S4