bad endgame : no mate with only Rook

[tissatussa]

while testing your v0.1 'PR42' (see my #2 ) against several engines, Elixer suddenly (?) played a bad endgame :

FEN: 8/8/8/8/8/5k2/r7/2B2K2 b - - 49 109

in the game elixir played Rc2 ?? but Ra1 is best : capturing the Bishop should win.
afterwards i let elixir evaluate this position (in SCID) and only the very first moment it considered Rc2.

how is this possible ?
my gut feeling says it's some Hash problem.
a few moves later elixir DID capture the Bishop but PR42 could not mate with only 1 Rook !? : this game was a draw ..

btw. this was a game with a fixed start position.

( full game here : elixir-v0.1-PR42-bad-endgame.zip )