Про технические термины не знаю, но с грамматической точки зрения кое-что бросилось в глаза. Кстати, там, где выделено красным, не совсем понятно, что имеется в виду. Как в оригинале было?
Rule 2:The level of utilization of a non-bottleneck is determined not by its own potential but by some other constraint in the system
There are four main combinations of X as a bottleneck and Y as a non-bottleneck. They demonstrate that the whole system can only be determined by the bottleneck irrespective of the direction of the parts flow [???].
In both cases, no matter whether the X feeding parts to Y or in reverse direction √ the Y feeding parts to X, it is important to produce as much [of what?] as can be sold. Besides you must take into consideration the fact that X is a bottleneck, i.e. it doesn't have extra capacity and you need all 100% capacity of the X machine to meet the demand.
In case the products should be worked on separately (one product flows through the bottleneck, the other does not) but mated [???] at the end of the production proсess into a single product, we must be oriented on demand and the bottleneck capacity.
If Y produced more than can be sold, that means you put up inventory.
In the other case √ the products are produced separately and are sold separately as well √ it seems at first glance that we can use both machines to 100% but in case of Y we should take into consideration the market demand. So the level of utilization of a non-bottleneck bottleneck [???] is determined not by its own potential but by some other constraint in the system.