diff --git a/format.c b/format.c
index e81ef32a..69e25e05 100644
--- a/format.c
+++ b/format.c
@@ -270,7 +270,7 @@ double mm_event_identity(const mm_reg1_t *r)
 		if (op == 1 || op == 2)
 			++n_gapo, n_gap += len;
 	}
-	return (double)r->mlen / (r->blen - r->p->n_ambi - n_gap + n_gapo);
+	return (double)r->mlen / (r->blen - n_gap + n_gapo);
 }
 
 static inline void write_tags(kstring_t *s, const mm_reg1_t *r)
diff --git a/main.c b/main.c
index 9481685c..02373a79 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "mmpriv.h"
 #include "ketopt.h"
 
-#define MM_VERSION "2.15-r905"
+#define MM_VERSION "2.15-r906-dirty"
 
 #ifdef __linux__
 #include <sys/resource.h>