Exception for 2-ancestry mixing, negative discriminant

Specification

\[\begin{array}{l} \\ 2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \end{array} \]

(FPCore (g h)
 :precision binary64
 (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))

\begin{array}{l}

\\
2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}

Reproduce

herbie shell --seed 2024283 
(FPCore (g h)
  :name "2-ancestry mixing, negative discriminant"
  :precision binary64
  (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))

Please file a bug report with this information.

Backtrace

eprintf: format string requires 0 arguments, given 1; arguments were: '(#s(si 5 4))		L	C
err-lsts->split-indices	/home/nightlies/herbie/zane-regimes-old/src/core/regimes.rkt	219	0
option-on-expr	/home/nightlies/herbie/zane-regimes-old/src/core/regimes.rkt	120	0
infer-splitpoints	/home/nightlies/herbie/zane-regimes-old/src/core/regimes.rkt	56	0
loop	/home/nightlies/herbie/zane-regimes-old/src/core/regimes.rkt	41	2
make-regime!	/home/nightlies/herbie/zane-regimes-old/src/core/mainloop.rkt	350	0
extract!	/home/nightlies/herbie/zane-regimes-old/src/core/mainloop.rkt	79	0
run-improve!	/home/nightlies/herbie/zane-regimes-old/src/core/mainloop.rkt	45	0
get-alternatives/report	/home/nightlies/herbie/zane-regimes-old/src/api/sandbox.rkt	186	0
(unnamed)	/home/nightlies/herbie/zane-regimes-old/src/api/sandbox.rkt	282	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24