Exception for Disney BSSRDF, PDF of scattering profile

Specification

\[\left(0 \leq s \land s \leq 256\right) \land \left(10^{-6} < r \land r < 1000000\right)\]

\[\begin{array}{l} \\ \frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} \end{array} \]

(FPCore (s r)
 :precision binary32
 (+
  (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r))
  (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))

\begin{array}{l}

\\
\frac{0.25 \cdot e^{\frac{-r}{s}}}{\left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r} + \frac{0.75 \cdot e^{\frac{-r}{3 \cdot s}}}{\left(\left(6 \cdot \mathsf{PI}\left(\right)\right) \cdot s\right) \cdot r}
\end{array}

Reproduce

herbie shell --seed 2024247 
(FPCore (s r)
  :name "Disney BSSRDF, PDF of scattering profile"
  :precision binary32
  :pre (and (and (<= 0.0 s) (<= s 256.0)) (and (< 1e-6 r) (< r 1000000.0)))
  (+ (/ (* 0.25 (exp (/ (- r) s))) (* (* (* 2.0 (PI)) s) r)) (/ (* 0.75 (exp (/ (- r) (* 3.0 s)))) (* (* (* 6.0 (PI)) s) r))))

Please file a bug report with this information.

Backtrace

error: contract violation expected: string? given: 'PI.f32		L	C
f374	.../match/compiler.rkt	559	40
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
loop	.../private/map.rkt	40	19
compile-expr	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	70	0
explain	/home/nightlies/herbie/bhargav-log-space/src/core/explain.rkt	613	0
explain!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	322	0
run-improve!	/home/nightlies/herbie/bhargav-log-space/src/core/mainloop.rkt	44	0
get-alternatives/report	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	186	0
(unnamed)	/home/nightlies/herbie/bhargav-log-space/src/api/sandbox.rkt	282	6
(unnamed)	/usr/local/racket/share/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/local/racket/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/local/racket/collects/racket/engine.rkt	42	24