diff --git a/main.c b/main.c
index b9e0add..c0e811d 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "mmpriv.h"
 #include "getopt.h"
 
-#define MM_VERSION "2.3-r537-dirty"
+#define MM_VERSION "2.3-r538-dirty"
 
 #ifdef __linux__
 #include <sys/resource.h>
diff --git a/sketch.c b/sketch.c
index d98fc70..9d21757 100644
--- a/sketch.c
+++ b/sketch.c
@@ -101,13 +101,13 @@ void mm_sketch(void *km, const char *str, int len, int w, int k, uint32_t rid, i
 				tq_push(&tq, skip_len);
 				kmer_span += skip_len;
 				if (tq.count > k) kmer_span -= tq_shift(&tq);
-				if (kmer_span >= 256) continue; // make sure $kmer_span does not take more than 8 bits
 			} else kmer_span = l + 1 < k? l + 1 : k;
 			kmer[0] = (kmer[0] << 2 | c) & mask;           // forward k-mer
 			kmer[1] = (kmer[1] >> 2) | (3ULL^c) << shift1; // reverse k-mer
 			if (kmer[0] == kmer[1]) continue; // skip "symmetric k-mers" as we don't know it strand
 			z = kmer[0] < kmer[1]? 0 : 1; // strand
-			if (++l >= k) {
+			++l;
+			if (l >= k && kmer_span < 256) {
 				info.x = hash64(kmer[z], mask) << 8 | kmer_span;
 				info.y = (uint64_t)rid<<32 | (uint32_t)i<<1 | z;
 			}