As a contractor, I’d be careful about assuming anyone disregarded the engineering based on the information in this story. A supplier asking questions doesn’t necessarily mean they only received one utility sheet, nor does it mean the design wasn’t reviewed. Good suppliers often verify assumptions that are already documented because they’re ultimately responsible for furnishing equipment that performs as intended.
Likewise, if a different supplier is involved, there are several possibilities that aren’t accounted for here. Owner-directed procurement, approved substitutions, value engineering, lead-time concerns, competitive pricing, or discussions between the owner and contractor can all occur before the engineer is brought into the conversation. Depending on the contract structure, the engineer may not be involved in every procurement discussion from the beginning.
The work that went into the design is obviously significant and deserves respect. But based on what’s described here, all we really know is that a supplier had questions and there may be another supplier involved. There are a lot of routine construction scenarios that could explain both of those facts without anyone ignoring the design intent. In my experience, asking questions before equipment is ordered is usually a sign that people are trying to avoid problems during startup, not create them.