book used was Arena's Perfect. Started by sac'in on f2, straight away.
Game here, and partial log.
[pgn][Event "40/15"]
[Site "TEST_SITE"]
[Date "2026.07.09"]
[Round "1"]
[White "magic refined"]
[Black "Bace_045"]
[Result "1-0"]
[ECO "C54"]
[WhiteElo "1600"]
[BlackElo "1500"]
[PlyCount "109"]
[EventDate "2026.??.??"]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d3 Bxf2+ 6. Kxf2 O-O 7. Na3 d6 8.
h3 Na5 9. Bb3 Nxb3 10. Qxb3 Rb8 11. Be3 Be6 12. Qa4 a6 13. Qa5 c6 14. Qxd8
Rbxd8 15. Ng5 h6 16. Nxe6 fxe6 17. Ke2 Rd7 18. Rhf1 d5 19. exd5 e4 20. dxe4
cxd5 21. e5 Ne4 22. Rxf8+ Kxf8 23. Rf1+ Rf7 24. Rxf7+ Kxf7 25. Nc2 a5 26. Kd3
h5 27. c4 Ng3 28. Bb6 a4 29. Ne3 dxc4+ 30. Nxc4 Ke7 31. Nd6 g5 32. Nxb7 g4 33.
hxg4 hxg4 34. Ke3 Nf5+ 35. Kf4 Nh6 36. Nc5 Nf7 37. Nxa4 Kd7 38. Bf2 Nh6 39.
Nc5+ Ke7 40. b4 Nf5 41. b5 g3 42. Bxg3 Kf7 43. b6 Nd4 44. Bh4 Nc6 45. a4 Nb8
46. a5 Nc6 47. b7 Kg7 48. a6 Kh7 49. a7 Kg6 50. b8=Q Nxb8 51. axb8=Q Kh6 52.
Ke4 Kh7 53. Qa8 Kg7 54. Kf4 Kh6 55. Ke4 1-0
[/pgn]
Log
Next move, imagines a non existing piece, judging by the log...2958454*2*Child Process Prio Adj: PID 5480 conhost.exe
2958454*2*Start calc, move no: 107
2958532 >second : time 74215
2958532 >second : otim 62533
2958532 >second : e4f4
2958532 <second : received - 'time 74215'
2958532 <second : received - 'otim 62533'
2958547 <second : received - 'e4f4'
2958563 <second : W 10:25.03 B 12:22.01
2958579 <second : B To Move
2958594 <second : 1 -23.83 0 22 g7f7 c5e6 f7e6
2958610 <second : 2 -27.44 0 44 g7h7 c5e6
2958625 <second : 3 -27.66 0 444 g7h6 a8e8 h6g7 c5e6
2958641 <second : 4 -27.81 0 640 g7h7 c5e6 h7h6 a8d5
2958657 <second : 5 -27.76 0 4170 g7h7 c5e6 h7g6 a8e4 g6h6
2958672 <second : 6 -27.84 0 9192 g7h7 a8d8 h7g6 d8h8
2958688 <second : 7 -39.98 0 94573 g7h7 a8f8 h7g6 f8g8 g6h6 f4e4 h6h5 g8g5 xxxx
2959063 <second : 8 -39.98 0 159097 g7h7 h4f6 h7g6
2959204 <second : 9 -39.98 0 351867 g7h6
2960735 <second : 10 -39.98 2 621706 g7h6 a8g8 h6h5 xxxx
2968329 <second : 11 -39.99 9 11169257 g7h6 c5e6 h6g6 a8d5
2983329 <second : time expired
2983329 <second : mate in 10
2983344 <second : 12 -39.99 24 13697024 g7h6 c5e6 h6g6 a8d5
2983360 <second : n/s: 552522, table: 6706182-90421-17817
2983375 <second : branch factor: 3.575 [3.794]
2983391 <second : depths searched: 1, 1, 1, 1, 1
2983407 <second : move g7h6
2983407*2*Found move:Kg7-h6
2983657 <second : W 10:25.03 B 11:57.03
2983657 <second : W To Move
2983672*1*Start calc, move no: 108
3005579*2*Child Process Prio Adj: PID 5480 conhost.exe
3005594*2*Start calc, move no: 109
3005657 >second : time 71728
3005657 >second : otim 60366
3005657 >second : f4e4
3005657 <second : received - 'time 71728'
3005672 <second : received - 'otim 60366'
3005688 <second : received - 'f4e4'
3005704 <second : W 10:03.06 B 11:57.02
3005704 <second : B To Move
3005719 <second : 1 +0.00 0 6 h6g7
3005719 <second : 2 +0.00 0 13 h6g7
3005735 <second : 3 +0.00 0 20 h6g7
3005750 <second : 4 +0.00 0 39 h6g7
3005766 <second : 5 +0.00 0 58 h6g7
3005782 <second : 6 +0.00 0 93 h6g7
3005797 <second : 7 +0.00 0 128 h6g7
3005813 <second : 8 +0.00 0 181 h6g7
3005829 <second : 9 +0.00 0 242 h6g7
3005844 <second : 10 +0.00 0 343 h6g7
3005860 <second : 11 +0.00 0 437 h6g7
3005875 <second : 12 +0.00 0 468 h6g7
3005891 <second : 13 +0.00 0 543 h6g7
3005907 <second : 14 +0.00 0 732 h6g7
3005922 <second : 15 +0.00 0 1205 h6g7
3005938 <second : 16 +0.00 0 2917 h6g7
3005954 <second : 17 +0.00 0 4246 h6g7
3005969 <second : 18 +0.00 0 7470 h6g7
3005985 <second : 19 +0.00 0 9840 h6g7
3006000 <second : 20 +0.00 0 16409 h6g7
3006016 <second : 21 +0.00 0 22382 h6g7
3006032 <second : 22 +0.00 0 46849 h6g7
3006047 <second : 23 +0.00 0 64428 h6g7
3006063 <second : 24 +0.00 0 109405 h6g7
3006079 <second : 25 +0.00 0 139255 h6g7
3006094 <second : 26 +0.00 0 177278 h6g7
3006110 <second : 27 +0.00 0 196672 h6g7
3006125 <second : 28 +0.00 0 239168 h6g7
3006141 <second : 29 +0.00 0 251628 h6g7
3006157 <second : 30 +0.00 0 301541 h6g7
3006172 <second : 31 +0.00 0 323436 h6g7
3006188 <second : 32 +0.00 0 386360 h6g7
3006204 <second : 33 +0.00 0 462040 h6g7
3006282 <second : 34 +0.00 0 565762 h6g7
3006422 <second : 35 +0.00 0 666155 h6g7
3006860 <second : 36 +0.00 1 1161743 h6g7
3006922 <second : 37 +0.00 1 1206052 h6g7
3007219 <second : 38 +0.00 1 1469624 h6g7
3007532 <second : 39 +0.00 1 1678410 a1f1
3007657 <second : 40 +0.00 1 1773625 a1f1
3008188 <second : 41 +0.00 2 2145149 a1f1
3009594 <second : 42 +0.00 3 3156266 a1f1
3012329 <second : 43 +0.00 6 4906671 a1f1
3013500 <second : 44 +0.00 7 5714006 a1f1
3724719 >second : ?
3724891****Tour**Game end: 1-0 {1-0 Black forfeits on time}
3724891****Tour**Last game won by magic refined with White in 55 moves
*"magic refined" is just a generic test name. Ran out of original names long ago
A few other varied engine bugs to report, soon.