The Menu button will appear as a button instead of the individual sections if the Zoom settings are not set at 100%. See below:
This can be easily reset by following the below steps:
For Google Chrome:
Select the at the top right-hand corner and using the + and - icons adjust the zoom to 100%.
Select the at the top right-hand corner and adjust the zoom settings to 100% by using the + and -. See below:
Once you have updated the zoom settings the layout will change. See below: