Wrong evaluation with multiple bishops of the same color

[dav1312]

Describe the issue

Stockfish can misevaluate positions when one player has multiple bishops of the same color. Of course this happens rarely (if ever) during real games, but it is still an interesting case worth documenting.

1b6/8/5b2/8/8/6kp/8/7K w - - 0 1 3b1b2/2b1b3/3b1b2/6b1/6kb/7p/8/7K w - - 0 1 3b4/2b1b3/3b1b2/6b1/6kp/6bp/8/7K w - - 0 1

8/p7/kpP5/qrp1b3/rpP2b2/pP6/P3K3/8 w - - 0 1 8/p7/kpP5/1rp1b3/rpB2b2/pP4b1/P3K3/8 w - - 0 1

(all draws)

Credits: https://arxiv.org/abs/2308.09175 https://www.reddit.com/r/chess/comments/16nytof/stockfish_thinks_black_is_winning/

Expected behavior

Correct evaluations according to the position.

Steps to reproduce

position fen 1b6/8/5b2/8/8/6kp/8/7K w - - 0 1
go infinite

Anything else?

No response

Operating system

All

Stockfish version

70ba9de

[Johnty01]

8/p7/kpP5/1rp1b3/rpB2b2/pP4b1/P3K3/8 w - - 0 1 Engine suggests to Pxa4, which worries me that only special case addition wont solve the issue, need to correct analysis with correct move order