iphone 7 - messages on lock screen showing separately from the same sender In the past, messages from the same sender would group as one notification on my lock screen e.g. Ann 7 messages

Since turning my phone on and off, suddenly multiple messages from the same sender are showing up separately. So if Ann sends me 7 messages, I'm getting 7 separate notifications on my lock screen. 

How do i get them to group together again?
You need to re-enable the grouping setting:

Go to Settings → Notifications → Messages → Scroll down to Notification Grouping → Set it to Automatic