Hired a surveyor for boundary dispute - he then took the neighbor as a client. Is this as bad as I think it is?

A surveyor doesn't advocate for his client nor the adjoiners. He determines the boundary independent of who hired him. He can't survey only your property. The neighbors' (plural) property must also be surveyed. You cannot enjoin him from considering evidence by saying "do not engage with the neighbor". In principal a surveyor delivers the same boundary opinion regardless of who has hired him. I have no idea what you mean by the survey was produced at the wrong scale. What is the right scale? I wouldn't deliver an AutoCAD dwg of a survey unless it was explicitly part of the contract. His note doesn't make any sense if he was producing a boundary survey. If he were producing a topographical design survey, instead of a boundary survey then the note does make sense. You seem to want to use the survey for construction. If so then your initial scope was lacking. 

I doubt you are crazy but the problems don't seem to be what you think they are. I'm not sure about California but many places require boundary surveys to be filed or placed with the county and available as part of the public record. 

You can't have it both ways when you ask for an independent opinion then believe the surveyor is serving someone else's interest when he works for the neighbor. By law he is required to give an independent unbiased opinion for both your survey and the neighbor's. He was never advocating for you to begin with thus it is not a conflict when he also does a survey for the neighbor.

What time frame for deliverables was agreed to in the contract? What were the deliverables agreed to in the contract? 6 months and a pdf file might not be unreasonable.

Big red flag.  Ethics here would demand that the surveyor gets it in writing and signed by both property owners that he is getting paid by both property owners to survey both properties as the same project.  He was made aware you were having a dispute with the adjoiner, he should not habe taken on the adjoiner as a client.

Some thoughts:

1.  A professional cannot disclaim away their professional obligations. Bugger the disclaimer. 

2. The syntax of the disclaimer reveals the surveyor's poor english skills.    

3. It doesn't matter what you told him if you can't prove that you did so. Do you have it in writing?

4. Is there a written contract?   

5. The professional surveyor's duty is to the public no matter who is footing the bill. The results of the survey should be the same regardless of who the client is. 

6. While I consider it unethical to gossip with the neighborhood about your plans I would not accept a job under your terms of secrecy. 

7. The collected survey data is the surveyor's property to use and reuse as he may see fit. What you get for your money is an expression of the surveyors opinion regarding your boundaries.   

8. It would be unethical to have you foot the bill for surveying the neighborhood and then charge the neighbor only a cut rate to stake their property. The neighbor should be paying their full share. This is how a savvy surveyor makes money in this business.    

I'm licensed in six states and they all require me to notify (typically in writing) all parties involved if I'm receiving compensation from more than one  party for work performed on the same parcel or project. I'd be surprised if California didn't have a similar rule in their standards of practice.

Some states allow a client to prohibit their PLS from sharing even boundary related information with neighbors, most don't. Did the contract you signed mention your prohibition on the PLS sharing information with your neighbor? 

Before going to the board of licensure and filing a formal complaint, give the surveyor a chance to explain themselves, preferably in writing. I'd assume incompetence over foul play so maybe there's still a chance the surveyor could make it right or at least reduce the damage.

"If a licensee provides professional services for two or more clients on a project or related projects, the licensee shall disclose in writing to those clients and property owners or their authorized representatives his or her relationship to those clients." 

 

On a side note, too many PLSs twist "public protection" into a blanket excuse for zero client confidentiality, deeming even modest NDAs unethical. I've signed (and would again) contracts limiting disclosures to abutters, while stipulating that all boundary determinations appear clearly in my final plat or report. Special requests like this justify a premium price.

Consider the Fourth Amendment: It shields our "persons, houses, papers, and effects" from unreasonable searches, demanding probable cause for any intrusion. As the Federalist Papers illuminate, this enshrines exclusivity—letting folks keep private matters private without being branded suspicious. You're innocent until proven guilty, not vice versa.

No PLS needs to spill boundary details to abutters if the client objects—just avoid lies, fraud, or obfuscation. In recording states, the info goes public anyway via filings; in non-recording ones, your state's emphasis on privacy makes sharing even less obligatory.