'Send' bar appearing at bottom of screen after ios 10 update

Hi,

Since updating to ios 10, I've occasionally encountered an issue where a 'send' bar appears across the bottom of my home screen and within apps, despite not being inside Messages. I'm not sure if this is something to do with responding to messages as they are received while the phone is locked/ when the message is opened from the top of the screen.

It's not too much of an issue and has only happened a few times but it doesn't disappear until I lock the phone and reopen it again. I wonder if anyone else has come across this?

Thanks.