Welcome @irod 
The Google Sheets add-on inserts rows at the bottom and then sorts them to the top. If your formatting is off it means the formatting at the very bottom of the sheet is off and that’s where it’s coming from. Sometimes this can happen if you copy/paste in manual data that has different formatting.
Recommend reformatting each column by selecting the column header letter at the top to ensure that last row’s formatting gets corrected too.
Last, you can fix the dropdown menu on the Category column using the steps in this guide: