When on vibrate mode, I can't get reminder notifications to appear when phone is locked?

[AC Question]

I have recently upgraded to the honor 7 and I have downloaded numerous 'hourly reminder apps' to remind me when to do various tasks throughout the day. However when my phone is on vibrate mode and locked, the reminder notification does not come up, but it will if I am playing on my phone. I am confused as to why no app I have downloaded actually notifies me when the screen is locked and on vibrate mode, but will when on loud.