Thanks for reporting. The error looks like a bug. HiGHS doesn’t (currently) support warm starts, so the code should silently ignore warmstarts (rather than erroring).
This is expected behavior. HiGHS doesn’t support warm starts. The second time works because we add starts to the JuMP model, and these are silently ignored when copying to the HiGHS backend.
Warm starts will be supported when the next upstream release of HiGHS is made.