Comment (by Roland Haas):

The change in behaviour happens in between the Herschel (ET_2014_11) which produces results identical to the paper and Hilbert (ET_2015_05) which produces results identical to Proca releases.

Hilbert is the release where GRHydro's default switched from F90 to C++ code. However that is not it as even running Hilbert with use_cxx_code = no does not recover Herschel's behaviour.

--
Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2175/test-single-stable-neutron-star-example