If a task or sale applies the expected prices and those prices later change, first check what changed and when. Another pricing app, ERP, inventory sync or manual edit can write to the same Shopify price fields.
Check one affected product
Open the task or sale's Details and compare its recorded prices with the current Shopify values.
Check whether the sale ended or the task was rolled back.
Check other apps and sync settings that can update price or compare at price.
If the difference only appears on the storefront, check the selected country and whether it uses fixed market prices.
A changed price is evidence of a later update, but does not identify which app or person made it. If you cannot find the cause, send support the task or sale title, one product and the approximate time the price changed.
Base product prices and fixed market prices are separate. See change prices in specific markets if the expected price appears in one country but not another.
Re-apply recorded prices on Premium
Re-apply writes the operation's saved prices again. It does not recalculate a fresh percentage from whatever price another system last wrote.
Automatic re-apply supports up to 10,000 price changes per task or sale. It is periodic: another system can still overwrite prices between runs. Check whether the affected products can be excluded from the competing price sync. If the competing update is unclear or prices keep changing unexpectedly, contact support with the task or sale title, one affected product and the approximate time of the change.
For an active sale, open Edit sale, enable Automatically re-apply price changes (every hour) under Advanced, and click Update.
For a task, select automatic re-apply when creating it. After the task completes, Details shows whether re-apply is enabled and its Last run when available. Do not create another percentage task over the same products just to add re-apply to an old task; ask support about your intended setup first.
Why the timing can differ
The re-apply minute in Settings is a minute within each hour. Setting it to 20 schedules the hourly run at twenty past, not every twenty minutes.
Processing takes time. On large stores, a run can last longer than an hour, and the next run waits for the previous one to finish. Last run being more than an hour ago does not by itself prove a failure. Check the operation's Details for status and progress. If the delay remains unexplained after checking progress, contact support with the task or sale title, status and how long it has been unchanged. Do not start an overlapping replacement task to force another run.
New products need a different setting
Re-apply does not add new products to an old task or sale. For an active sale, use Actions > Check changes, or enable Premium condition tracking for hourly checks. See add missing products to an active sale.