Usually they are. It makes manufacturing easier to get right.
GingisK wrote: “Usually they are. It makes manufacturing easier to get right.”
Not necessarily. I managed a large scale production program for DoD. Any change of supplier or process or component results in a lot change since every component of a lot must be identical across the lot. You get into a situation where you run out of a component and must get a new lot of that component which generates a lot change at the product level. For example, if you are using something as simple as distilled water and you get a new batch, you either have to roll the lot or get a waiver. While uniformity of lot size is an objective, it doesn’t always work out that way.
The article in question does not provide any information on lot sizes. The number of adverse effects maybe purely a function of lot sizes.