Reinstalling Rocket League can sometimes fix odd problems. You will first need to uninstall, then redownload Rocket League (This will not delete game save data).
To uninstall Rocket League:
- Highlight Rocket League on the Home Screen
- Press the + button on the right Joy-Con
- Select Manage Software
- Select Rocket League
- Select Manage Software
- Select Delete Software
- Select Delete to confirm
To re-download Rocket League:
- Open the eShop
- Select the profile used to purchase Rocket League
- Select the profile in the upper right corner
- Select Redownload from the menu on the left