Welcome to Android Central forums. Just a couple of silly questions before offering advice.
What device do you have?
Have you carefully touched each to see if they both do the same thing? They are kind of close together and I'm mostly curious, just to know.
Anyway, have you changed the keyboard theme/style, either recently or as a test to see if this is effected?
I suspect that this may just be a slight bug and clearing the app cache could correct it. Open your app drawer>locate the Gboard app>press and hold the icon until the information (i) appears>Storage>Clear Cache.
Let us know what you find.