diff --git a/pimd/CAVEATS b/pimd/CAVEATS
index 05a439b..b1f1a03 100644
--- a/pimd/CAVEATS
+++ b/pimd/CAVEATS
@@ -158,4 +158,20 @@
     2014/02/14 16:30:14 PIM: pim_zebra.c del_oif: nonexistent protocol mask 1 removed OIF eth0 (vif_index=2, min_ttl=0) from channel (S,G)=(1.2.3.4,232.1.2.3)
     2014/02/14 16:30:14 PIM: Assertion `!IGMP_SOURCE_TEST_FORWARDING(source->source_flags)' failed in file pim_igmpv3.c, line 412, function igmp_source_delete
 
+C19 Provision to prevent group mode clash
+
+    Beware group mode clash. A host/application issuing IGMPv2
+    any-source joins for a group will disrupt SSM multicast for that
+    group.
+
+    For instance, support for source-specific static igmp WILL FAIL if
+    there is host/application issuing IGMPv2 any-source joins for the
+    same group.
+
+    The reason is the IGMPv2 any-source join forces qpimd to switch
+    the group mode to ASM (any-source multicast); however, qpimd is
+    unable to program ASM groups into the kernel; multicast won't
+    flow. There could be some provision to prevent such a behavior,
+    but currently there is none.
+
 -x-