The AI threatens one of my white knights (at c3) with a black pawn. I withdraw it (e2), it advances a pawn elsewhere (h5), then I move a pawn from c2 to c4, passing over the square that was occupied by the knight. On the next turn, the AI is able to move the pawn diagonally from d4 to c3, which is empty, and the pawn I just moved (at c4) gets captured. Tried the same move sequence using two human players, and it worked the same; when I click on the black pawn, c3, an empty square, becomes blue, and when I move there the white pawn at c4 gets captured.

This is glchess 2.22.3 on Ubuntu.

Here's the file from /.gnome2/glchess/history/:
[Event "Human versus GNU Chess"]
[Site "?"]
[Date "2008.08.02"]
[Round "?"]
[White "White"]
[Black "GNU Chess"]
[Result "*"]
[BlackAI "GNU Chess"]
[BlackLevel "easy"]

1. e4 e5 2. f3 Nc6 3. Nc3 Nf6 4. a3 d5 5. b4 Be6 6. d3 d4 7. Nce2 h5 8. c4 dxc3
*

Here's the in-game GNU chess log:
xboard
easy
depth 1
force
e2e4
force
e7e5
force
f2f3
force
b8c6
force
b1c3
force
g8f6
force
a2a3
force
d7d5
force
b2b4
force
c8e6
force
d2d3
force
d5d4
force
c3e2
force
h7h5
force
c2c4
force
d4c3
Chess
Adjusting HashSize to 1024 slots
Search to a depth of 1
1. e2e4
1. e7e5
2. f2f3
2. b8c6
3. b1c3
3. g8f6
4. a2a3
4. d7d5
5. b2b4
5. c8e6
6. d2d3
6. d5d4
7. c3e2
7. h7h5
8. c2c4
8. d4c3