diff --git a/src/Frag.cc b/src/Frag.cc
index 9bd16a71c9..04298e14ad 100644
--- a/src/Frag.cc
+++ b/src/Frag.cc
@@ -52,8 +52,6 @@ FragReassembler::FragReassembler(NetSessions* arg_s,
 	frag_size = 0;	// flag meaning "not known"
 	next_proto = ip->NextProto();
 
-	AddFragment(t, ip, pkt);
-
 	if ( frag_timeout != 0.0 )
 		{
 		expire_timer = new FragTimer(this, t + frag_timeout);
@@ -61,6 +59,8 @@ FragReassembler::FragReassembler(NetSessions* arg_s,
 		}
 	else
 		expire_timer = 0;
+
+	AddFragment(t, ip, pkt);
 	}
 
 FragReassembler::~FragReassembler()
diff --git a/testing/btest/Baseline/core.ipv6-atomic-frag/output b/testing/btest/Baseline/core.ipv6-atomic-frag/output
new file mode 100644
index 0000000000..4a628a4bdc
--- /dev/null
+++ b/testing/btest/Baseline/core.ipv6-atomic-frag/output
@@ -0,0 +1,4 @@
+[orig_h=2001:db8:1::2, orig_p=36951/tcp, resp_h=2001:db8:1::1, resp_p=80/tcp]
+[orig_h=2001:db8:1::2, orig_p=59694/tcp, resp_h=2001:db8:1::1, resp_p=80/tcp]
+[orig_h=2001:db8:1::2, orig_p=27393/tcp, resp_h=2001:db8:1::1, resp_p=80/tcp]
+[orig_h=2001:db8:1::2, orig_p=45805/tcp, resp_h=2001:db8:1::1, resp_p=80/tcp]
diff --git a/testing/btest/Traces/ipv6-http-atomic-frag.trace b/testing/btest/Traces/ipv6-http-atomic-frag.trace
new file mode 100644
index 0000000000..d5d9db276c
Binary files /dev/null and b/testing/btest/Traces/ipv6-http-atomic-frag.trace differ
diff --git a/testing/btest/core/ipv6-atomic-frag.test b/testing/btest/core/ipv6-atomic-frag.test
new file mode 100644
index 0000000000..0829d8e973
--- /dev/null
+++ b/testing/btest/core/ipv6-atomic-frag.test
@@ -0,0 +1,7 @@
+# @TEST-EXEC: bro -r $TRACES/ipv6-http-atomic-frag.trace %INPUT >output
+# @TEST-EXEC: btest-diff output
+
+event new_connection(c: connection)
+	{
+	print c$id;
+	}