I did some testing. I can't see problem with version 1.4 as i remember only with 1.6. And it happens with 512 MB hash and 2 CPU at least (not with 256MB

). Another example:

[D]2k5/8/3KN3/2NNN3/8/8/3q4/8 w - - 0 1

Analysis by Critter 1.6 64-bit 2CPU 512MB:

...

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qg1 4.Nb5 Qc1 5.Ne7 Qc4 6.Kb6 Qxb5+ 7.Kxb5 Ka8 8.Kb6 Kb8 9.Na6+ Ka8 10.Nec7#

+- (#10) Depth: 23/38 00:00:01 6795kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qc2 4.Nb4 Qh7 5.Nd7+ Qxd7+ 6.Kxd7 Ka7 7.Kc6 Kb8 8.Kb6 Ka8 9.Nc7+ Kb8 10.Nba6#

+- (#10) Depth: 24/38 00:00:02 12702kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qh7 4.Nd7+ Qxd7+ 5.Kxd7 Ka7 6.Kc6 Ka8 7.Nb6+ Ka7 8.Nc7 Kb8 9.Nd7+ Ka7 10.Ndb5#

+- (#9) Depth: 25/38 00:00:03 21392kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qc2 4.Nb4 Qh7 5.Nd7+ Qxd7+ 6.Kxd7 Ka7 7.Kc6 Kb8 8.Kb6 Ka8 9.Nc7+ Kb8 10.Nba6#

+- (#10) Depth: 26/38 00:00:06 35607kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qh7 4.Nd7+ Qxd7+ 5.Kxd7 Ka7 6.Kc6 Ka8 7.Nb6+ Ka7 8.Nc7 Kb8 9.Nd7+ Ka7 10.Ndb5#

+- (#10) Depth: 27/38 00:00:11 66315kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qc2 4.Nb4 Qh7 5.Nd7+ Qxd7+ 6.Kxd7 Ka7 7.Kc6 Kb8 8.Kb6 Ka8 9.Nc7+ Kb8 10.Nba6#

+- (#10) Depth: 28/38 00:00:15 93175kN

1.Nc4 Qh2+ 2.Kc6 Kb8 3.Nd6 Qh7 4.Nd7+ Qxd7+ 5.Kxd7 Ka7 6.Kc6 Ka8 7.Nb6+ Ka7 8.Nc7 Kb8 9.Nd7+ Ka7 10.Ndb5#

+- (#9) Depth: 29/38 00:00:22 139mN

Now there are mate in 9 score but mate in 10 main lines..