The bug locates at line 117–134 of src/EvtGenBase/EvtBtoXsll.cpp (see the attachment below). The problem is that when we manually set the cutoff of Xs mass (_mxmin) in the decfile in the following way:
Decay B+sig
1.0 Xsu mu+ mu- PHOTOS BTOXSLL 4.8 0.2 0.0 0.461 1.1;
Enddecay
values of other parameters (_mb, _ms, _mq and _pf) are set to default values regardless of what we intended to set.