When it finds mate it many times can't decide correct length. Example
[D]8/8/6k1/Q7/8/8/3p1pp1/3Kbrrb w - - bm #20;
16/40 00:00 7 695k 9 249k +M24 Qa5-a6+
17/35 00:00 7 772k 9 231k +M24 Qa5-a6+
18/50 00:00 8 896k 9 296k +M21 Qa5-a6+
19/49 00:01 9 661k 9 326k +M29 Qa5-a7
20/43 00:01 9 774k 9 318k +M21 Qa5-a7
21/41 00:01 9 885k 9 299k +M21 Qa5-a7
22/48 00:01 10 893k 9 286k +M21 Qa5-b5
23/43 00:01 11 310k 9 278k +M21 Qa5-b5
24/45 00:01 11 815k 9 259k +M20 Qa5-b5
25/53 00:01 14 077k 9 267k +M21 Qa5-b5
26/55 00:02 20 322k 9 288k +M20 Qa5-b5
27/47 00:48 412 068k 8 431k +M21 Qa5-b5
28/41 00:49 415 281k 8 433k +M21 Qa5-b5
But this is minor bug for great engine.
One issue with Crystal 27.8.2019
Moderators: hgm, Rebel, chrisw