On a whim I attempted to create a Q2 941 and leaving those sections simply blank encountered no errors other than being disallowed to file until after the quarter ends on next Tuesday. Even if you plan on mailing the form I would suggest waiting until a week from now so that your signature and postmark are validly after the end of the quarter.
Did you check for payroll updates before running the form? The blanks for retention credits or family leave pay are not required that I can tell and leaving blank or entering 0 will have same effect