Case I
I approved centimetres at the screen while the receiver still expected metres
In 2021, as engineering director, I approved an interface change that expressed curtain width in centimetres. A receiving component still interpreted the bare value as metres. The synthetic example was simple: 2.35 metres became 235 centimetres, then the number 235 was read as 235 metres. Eighteen of 120 test quotations exposed the mismatch. The arithmetic was correct at each local step only under assumptions that the two components did not share.
Product colleagues wanted the interface change to remain within its planned release because the visible input was clearer to customers. I agreed with the intended usability improvement, but the receiving behaviour made that release unacceptable in its current form. We held it and allocated ₹41 lakh to the unit contract and its tests. My earlier approval remained part of the account; I had examined the displayed change more closely than the meaning another component would assign to it.
The correction required engineering teams to describe the value with its unit and receiving expectation, then test the relevant boundaries. Technical-design head Yusuf Tevqeri retained physical-product feasibility. The software team could not certify a customer's actual measurement or decide every manufacturing constraint through a numeric conversion. This fictional case contains no live wrong order, no pricing-policy change and no assertion that every other interface was already sound.
The result was a held release and a funded repair to the contract between components. I would not reduce the lesson to asking developers to multiply or divide more carefully. The important failure was that a plausible number travelled without enough explicit meaning for the receiver to interpret it correctly. A CTO needs to ask where that meaning is established and how an apparently local improvement will be understood by the rest of the customer journey.