I've seen this addressed in other posts, but I think the answer provided was for Windows users.
This was the answer I'm referring to:
Quicken > Preferences > Connected Services
in the upper menu at the top of the screen while Quicken is open. Then you would proceed to remove the check mark in the box next to
Use posted date for matched transactions (instead of the date you enter manually)
Is there a simple answer for Mac? There usually isn't, and Quicken is the one software that is incredibly more user friendly in Windows.