“No manager sign-off” does not mean a charge was rejected or improper. Every purchase here went through at the register — the card worked. The Town's Procurement and Vendor Card Policy sets a second step: the cardholder approves the charge, then it is routed to the department head or a designee for review and approval, no later than the 5th of the following month. On these charges that second step cleared automatically, with no person named. The cardholder step was completed nearly every time; this is the one that was not.
Flags are arithmetic patterns, not findings. Each one has an innocent explanation as often as not — a duplicate charge may be two genuine identical invoices, a weekend charge may be a firefighter buying supplies on shift. They mark where to look, and every flag links straight to the underlying charges so a claim can be checked before it's made.