Your books changed after you filed

When you mark a period as filed, TALISK_HQ keeps a copy of the worksheet exactly as it stood. That copy never changes. So the Tax Summary for a filed period always shows what you sent to the CRA, even if your books move afterwards.

Books do move afterwards. A supplier invoice arrives late and is dated inside the quarter. A bank feed backfills a charge you had missed. Either way the expense belongs to that period, so it gets recorded there.

When that happens you get a card on your books-health panel saying your books have changed since you filed, which figure moved, and by how much.

What to do about it

You do not amend the return. The one you filed was correct with the information you had.

For a missed input tax credit, claim it on your next return instead. The CRA gives you up to four years to claim an ITC, and claiming it late is normal practice, not a correction.

For anything larger, or a change that moves the net tax by a lot, ask your accountant whether it needs an adjustment. That is a judgment call about materiality, and it is theirs to make.

Seeing what changed

Open Ledger › Accounting › Journal and set the period to the one that was filed. Entries posted after you filed are the ones that moved the figure. The card tells you how many there are.

Periods filed before this existed

A period you filed before TALISK_HQ started keeping a copy has nothing frozen to compare against, so its figures are rebuilt from your books when you open it. The page says so rather than presenting a fresh calculation as the return you sent. Those periods get no change card, because there is no baseline to measure against.

Stopping it happening

Locking a period is what keeps entries out of it in the first place. Set the lock date on Ledger › Accounting › Period Lock, or leave the "lock the books through this period" box ticked when you mark a return as filed, which is the default.