There are two locations to check date labels; LeanLaw's Invoice Presentation and QuickBooks Online's Custom Form Styles.

Starting with LeanLaw, Make date part of invoice description condenses the Date field into the Description field. If turned off, the Date column will reappear.

In QuickBooks, under Custom Form Styles, you'll find the Date column. If you've already set the Date in LeanLaw, make sure not to set it here as well. Doing so will give you multiple date columns.