Twin A
no editLeft exactly as it was when the customer paid.
- Items
- $372.00
- 10% promotion
- −$37.20
- Shipping
- $5.00
- State
- PaymentSettled
Total$339.80
The order was already paid. Only its billing city changed.
We froze a real store the moment an order was paid, copied it twice, and edited one copy. The customer's discount vanished from the receipt.
- Order
- 4WQVKNWLNGQ5TFV6
- Paid
- $339.80, PaymentSettled
- Promotion
- 10% off orders $100+
Twin B
driftedPromotion switched off after payment, then only the billing city edited.
- Items
- $372.00
- 10% promotion
−$37.20removed- Shipping
- $5.00
- State
- Modifying
Total$377.00
A $339.80 → B $377.00Discount dropped after payment. Nothing the customer bought changed.+$37.20
Both twins are CreateOS forks of one paused store. The Vendure server kept running through each fork, so they start from the same state in memory and on disk.
How the twins were made
Every step ran against a real Vendure 3.7.3 store in a CreateOS sandbox. Payments used Vendure's test handler, so no money moved.
- Seed a paid order
automatic promotion → order over $100 → PaymentSettled - Freeze the store
cos fork pauses the running sandbox and snapshots it - Copy it twice
twin A · twin B, each with the store still running - Edit twin B only
updatePromotion(enabled: false) → modifyOrder(billing city) - Compare receipts
A $339.80 · B $377.00 · difference +$37.20
Two controls rule out coincidence
Run on twin A, where the promotion is still on.
| Control | Action | Result | Verdict |
|---|---|---|---|
| No drift | The same billing-city edit | $339.80, discount kept | Pass |
| Eligible promotion | Dry run, quantity 1 → 2 | $674.60, −$74.40 | Pass |
The address edit on its own is harmless. The total drifts only when a promotion changes after payment, and real edits still reprice correctly.
Second finding · live agent run
Nobody switched the promotion off. It simply expired.
An AI agent in twin B wrote and ran its own probe: a scheduled promotion ran out, then only the address on a paid order was edited, and the total rose from $1,397.12 to $1,407.92. Every figure was confirmed in the store's database.
+$10.80
- Model
- Opus 5.5 via OpenRouter
- Runner
- Claude Code in CreateOS
- Run
- 10 turns · 3 min 22 s
- Order
- 9ZHV3PFUU5JHNWBG