diff --git a/src/msolve/duplicate.c b/src/msolve/duplicate.c
index f1db24f0..5cf3742e 100644
--- a/src/msolve/duplicate.c
+++ b/src/msolve/duplicate.c
@@ -394,7 +394,7 @@ static inline void duplicate_data_mthread_gbtrace(int nthreads,
                                                   trace_t **btrace){
 
 
-  const len_t len = num_gb[0] * (st->nvars);
+  const len_t len = num_gb[0] * (st->nvars - st->nev);
 
   for(int i = 0; i < nthreads; i++){
     leadmons_current[i] = (int32_t *)calloc(len, sizeof(int32_t));