From Thomas Sowell's Basic Economics - "Inflation is a _general_ rise in prices. The national price level rises for the same reason that prices of particular goods and services rise - namely, that there is more demanded than supplied at a given price. When people have more money, they tend to spend more. Without a corresponding increase in the volume of output, the prices of existing goods and services simply rise because the quantity demanded exceeds the quantity supplied at current prices and either people bid against each other during the shortage or sellers realize the increased demand for their products at existing prices and raise their prices accordingly."
Note the emphasis on general. There is no reason to expect that the outcome of customers bidding against each other, or producers increasing prices to meet new demand levels would be uniform across all goods and services, furthermore, you would expect that the existing climate of the time would wildly swing the actors' actions involved in these bidding & pricing exercises.