In effect, this isn't an engineering failure at all. Rather it's a complete and utter failure to communicate. I liked the solution though: Sue the engineer so their liability insurance covers their ass.
I worked on a major river crossing of the Missouri River 15 years ago. Teamed with another firm: They did the road on the north side, and our firm did the bridge and the roadway on the south side. We had a single vertical datum, but because the two sides of the river were in differing counties there was potential for horizontal coordinate system differences. No problemo - Herr Duck met with the other firm's roadway lead, a common system was agreed upon, I issued a memo documenting the mutually agreed upon system we'd use and the project progressed. Fast forward 15 months to our final submittal to MoDOT...
We were the prime consultant, so the other firm shipped their deliverables to us and we bundled them to submit together. But first, I spend a few days reviewing their work - because while they're liable for it professionally, we're the prime and it's what we do. First thing I do is review datums and then the main roadway alignment coordinates. The datum info checks, but coordinates indicate their horizontal alignment is about 5-1/2" offset from and parallel to ours. Communication ensues, I reference the memo, they grouse and want something different, I refuse and bosses get involved.
Basically we told them our plans were going to build off our alignment, and if they thought the client would be happy with their road being 5-1/2" offset from and not aligning with a new half mile long interstate highway bridge, we'd submit the plans as-is BUT would advise the client of the discrepancy. They caved, corrected and resubmitted.
Supposedly they were a "premier" firm...
So yeah, shit like that happens more than you'd think.