Some things to note:
Gift card balances are held at a "home" location, where the gift card record was originally created and then the gift card "account" is replicated to the rest of the locations. When a gift card is used or re-loaded at another the sister location reaches out to the home location to update the balance. Outstanding/Giftcard Transaction reports only display details on the giftcards that call that location "home". Accounting reports, such as the Sales Summary report's Tenders By Payment Date section for example, will show payments for any gift card used at a payment method originating from any location.
What the information above means, is that the Tenders By Payment Date amount can and will likely be different than any outstanding liability balance you would pull from a single location.
Sales Summary Report > Tenders By Payment Date > Gift Card & Fast Cash
Gathering gift card payments taken (gift card balance used):
Paid amount will show payment records on a check from using a gift card as the payment method.
Refund amount will show payment records on a check from using a gift card as the refund method.
Sales Summary Report > Liabilities > Gift Card & Fast Cash
This amount is going to be gift cards being loaded on a check when being sold as a gift card product. This does NOT include balances added to gift cards by any other method (refunds, loaded through admin portal, etc.). The check does need to be closed to include a value here, but that could be closed with any payment method.
Oustanding Credits Report:
Will show the outstanding credit balance at that exact moment the report was ran. This should NOT be used to export the report and filter by the dates to see what the past credit liability amounts were.
Giftcard Transaction Report:
Shows all giftcard transactions on an individual transaction level. This should be more accurate at showing what the past liabilities balance was at a specific date if you choose the beginning date to be "at the beginning of time" (aka, before the location opened). For example, if you choose a start date in 2021 and then choose the end date to be same day, the total would be the same as the total in your Outstanding Credits report.