A bug? It's an exchange up and inexorably winning, when suddenly it steps into a two-move mate.
score depth nodes time score depth nodes time
d2d4 0 0 0 9 d7d5 0 0 0 0
g1f3 0 0 0 9 g8f6 0 0 0 0
e2e3 0 0 0 9 e7e6 -5 4 6737 1
f1d3 0 0 0 6 b8c6 -7 5 21005 3
e1g1 0 0 0 6 f8d6 -18 5 19203 3
c2c4 0 0 0 10 d5c4 0 3 2952 1
d3c4 0 0 0 3 e8g8 -1 4 13203 2
b1c3 0 0 0 5 c8d7 -5 4 16703 2
a2a3 0 0 0 12 a7a6 4 4 14154 2
b2b4 0 0 0 5 a6a5 17 2 1291 1
b4b5 0 0 0 11 c6a7 -19 4 20271 2
a3a4 0 0 0 5 d8e7 -29 4 14353 2
d1b3 0 0 0 9 a7c8 -32 4 13554 2
e3e4 0 0 0 54 d6b4 -47 4 12057 1
c1g5 0 0 0 29 h7h6 -43 3 4071 1
g5f6 0 0 0 53 e7f6 -34 4 11418 1
e4e5 0 0 0 7 f6g6 -33 4 18343 1
a1d1 0 0 0 34 c8b6 -15 4 14517 1
c4d3 0 0 0 6 g6g4 -33 3 2407 1
h2h3 0 0 0 32 g4h5 -68 4 15845 1
c3e4 0 0 0 37 f7f6 -57 4 15554 2
e4c5 0 0 0 74 b4c5 -77 4 23321 1
d4c5 0 0 0 15 b6d5 -83 4 11646 1
c5c6 0 0 0 39 b7c6 22 4 31422 1
b5c6 0 0 0 7 d7c6 21 4 20952 2
f3d4 0 0 0 136 a8b8 33 4 18267 1
b3a2 0 0 0 4 c6d7 37 4 22052 2
d3c4 0 0 0 32 d5c3 170 3 6496 1
c4e6 0 0 0 35 g8h8 133 5 33486 2
a2c4 0 0 0 30 c3d1 187 4 23354 2
e6d7 0 0 0 35 f6e5 146 4 21674 2
d4e6 0 0 0 28 f8f7 134 3 3176 1
c4c7 0 0 0 41 b8g8 89 4 20014 2
c7c6 0 0 0 232 d1f2 257 4 23156 2
f1c1 0 0 0 262 f2d3 326 4 23493 1
c1b1 0 0 0 24 h5h4 347 3 4262 1
d7e8 0 0 0 47 f7f6 352 4 22120 1
c6d7 0 0 0 37 h4g3 333 4 20904 2
e8f7 0 0 0 67 d3c5 359 3 3714 1
e6c5 0 0 0 13 g3f2 327 4 20436 1
g1h1 0 0 0 9 f6f7 313 4 15438 1
d7d5 0 0 0 34 f7f5 298 4 15004 2
c5e4 0 0 0 23 f2d4 316 3 2690 1
d5c6 0 0 0 20 g8f8 346 4 10657 1
b1b7 0 0 0 26 g7g5 501 4 11860 1
c6h6 0 0 0 61 h8g8 -9997 1 160 0
h6g7 0 0 0 4