Happens for the Tamagawa number for curve 588.a.18816.1.
So I believe what happens, is the following. The cluster picture is (****(**)) and Frobenius acts cyclically on the first four roots, and cyclically on the two in the twin. Now the subcluster (**) is invariant under Frobenius, but its theta_squared is not, because the center [sic] of (**) is not invariant under Frobenius.
Happens for the Tamagawa number for curve 588.a.18816.1.
So I believe what happens, is the following. The cluster picture is
(****(**))
and Frobenius acts cyclically on the first four roots, and cyclically on the two in the twin. Now the subcluster(**)
is invariant under Frobenius, but its theta_squared is not, because the center [sic] of(**)
is not invariant under Frobenius.