first method in network performance test takes longer

I discovered by accident that running the same test with the same refinements multiple times, the first one iteration twice as long.

I ran Bin2 + solver SOS with refinement = 4 on the lossy network problem.

====================================================================================================
MIP Bilinear Approximations (HiGHS)
  Refinement = num_segments for SOS2 methods, depth for Sawtooth
====================================================================================================
Method             Ref   Vars Constrs   Bins    Objective    Gap(%)  Mean Resid  Max Resid  Time(s)
----------------------------------------------------------------------------------------------------
Bin2+sSOS            2    190     495      0     0.964218        -    1.52e-01   4.48e+01   3.0377

Bin2+Saw             2    190     495      0     0.964218        -    1.52e-01   4.48e+01   1.1425

HybS+sSOS            2    190     495      0     0.964218        -    1.52e-01   4.48e+01   1.1417

HybS+Saw             2    190     495      0     0.964218        -    1.52e-01   4.48e+01   1.1407

====================================================================================================

The methods and ref columns do not reflect the actual methods and refinements.

Start by reproducing the network performance test with the lossy network problem, Bin2, solver SOS, and refinement 4, comparing the first and repeated iterations. Trace where the method, refinement, and timing columns are produced; done means repeated runs are measured consistently and the displayed method and refinement values match the actual execution.