I've been googling like crazy but can't find any information on this.
If someone has 2 passports and applies for travel health insurance using one citizenship, does that mean that travelling on the passport not applied from nulls the travel health insurance?
Health Insurance as a Dual Citizen
Re: Health Insurance as a Dual Citizen
It would seem unlikely they would know or care what passport you were using, but if you're concerned I'd just ask the insurance company.