The shortest stoner is found in 13 moves.
Article in Japanese: https://qiita.com/Nyanyan_Cube/items/bd0f808dbece005256e6
One example is: e6d6c6d7c8b6c7f7f6e8f8g8b7
The full solution is:
0 stoner-like solutions found but no successful stoner path found at depth 0 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 1 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 2 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 3 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 4 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 5 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 6 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 7 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 8 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 9 in 0 ms
0 stoner-like solutions found but no successful stoner path found at depth 10 in 1 ms
0 stoner-like solutions found but no successful stoner path found at depth 11 in 3 ms
6 stoner-like solutions found but no successful stoner path found at depth 12 in 28 ms
301 stoner-like solutions found and 41 successful stoners found at depth 13 in 4111 ms
d3c5d6e7b6d2c6a6d7e8f8g8b7 longest way to escape: 0 moves
e6d6c5b6c6e7c7d8f8f6e8g8b7 longest way to escape: 0 moves
e6d6c5b6c7e7c6d8f8f6e8g8b7 longest way to escape: 0 moves
e6d6c6f6c4e7e8b6c7d8f8g8b7 longest way to escape: 0 moves
e6d6c6d7c8b6c5e8e7f7f8g8b7 longest way to escape: 0 moves
e6d6c6d7c8b6c7f7f6e8f8g8b7 longest way to escape: 0 moves
e6d6c7f6c6e7e8d8f8b6c4g8b7 longest way to escape: 0 moves
e6d6c7f6c6e7e8d8f8b6b7g8c4 longest way to escape: 0 moves
e6d6c7f6c6e7e8d8f8g8c4b6b7 longest way to escape: 0 moves
e6d6c7f6c6e7f8b6b7d8e8g8c4 longest way to escape: 0 moves
e6d6c7f6c6e7f8d8c4b6e8g8b7 longest way to escape: 0 moves
e6d6c7f6c6e7f8d8e8b6c4g8b7 longest way to escape: 0 moves
e6d6c7f6c6e7f8d8e8b6b7g8c4 longest way to escape: 0 moves
e6d6c7f6c6e7f8d8e8g8c4b6b7 longest way to escape: 0 moves
e6d6c7f6c6e7f8b6c4d8e8g8b7 longest way to escape: 0 moves
c4c5d6e7b6d3c6a6d7e8f8g8b7 longest way to escape: 0 moves
c4c5d6e7b5d3c6a6d7e8f8g8b7 longest way to escape: 0 moves
f5f6e6d6e7d8c6b6d7e8f8g8b7 longest way to escape: 2 moves
f5f6e6d6c6b6e7d8d7e8f8g8b7 longest way to escape: 2 moves
f5d6c6f6e6d7c8b6f7g8f8e8b7 longest way to escape: 2 moves
f5d6c6f6e6d7f7g8c8b6f8e8b7 longest way to escape: 2 moves
e6f6f5d6f7g8c6d7c8b6f8e8b7 longest way to escape: 2 moves
f5d6c6f6e6d7f7b6c8g8f8e8b7 longest way to escape: 2 moves
f5d6c6f6e6b6e7d8d7e8f8g8b7 longest way to escape: 2 moves
c4c5d6e7c6b6d7e8f8g8b7c7c8 longest way to escape: 2 moves
c4c5d6e7c6b6d7e8b7c7f8g8c8 longest way to escape: 2 moves
c4c5d6e7c6b4b6a6d7e8f8g8b7 longest way to escape: 2 moves
c4c5d6e7b6b4c6a6d7e8f8g8b7 longest way to escape: 2 moves
f5f6e6d6f7g8c6d7c8b6f8e8b7 longest way to escape: 2 moves
f5f6f7d6e6g8c6d7c8b6f8e8b7 longest way to escape: 2 moves
e6d6c6f6f5b6e7d8d7e8f8g8b7 longest way to escape: 2 moves
e6d6c6f6f5d7f7b6c8g8f8e8b7 longest way to escape: 2 moves
e6d6c6f6f5d7f7g8c8b6f8e8b7 longest way to escape: 2 moves
e6d6c6f6f5d7c8b6f7g8f8e8b7 longest way to escape: 2 moves
e6f6f5d6c6b6e7d8d7e8f8g8b7 longest way to escape: 2 moves
e6f6f5d6e7d8c6b6d7e8f8g8b7 longest way to escape: 2 moves
f5f6e6d6f7g8c6d7e8b6f8d8b7 longest way to escape: 6 moves
f5f6f7d6e6g8c6d7e8b6f8d8b7 longest way to escape: 6 moves
e6d6c6f6d3b6d7e8e7d8f8g8b7 longest way to escape: 6 moves
e6d6c6f6d3b6e7d8d7e8f8g8b7 longest way to escape: 6 moves
e6f6f5d6f7g8c6d7e8b6f8d8b7 longest way to escape: 6 moves