diff --git a/ChangeLog b/ChangeLog
index 159818586d..382d0dcaff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+1828.	[bug]		andrei
+	Fix trivial logic error in handling the "lease4-update" command
+	manifesting itself on v4 if multi-threading is enabled.
+	Notable affected environment is a HA with the
+	"send-lease-updates" configuration setting explicitly set to
+	true. Prior to this fix, lease updates would not go through to
+	other HA nodes, even though some log lines would say they would.
+	A simple workaround prior to this fix is to disable
+	multi-threading.
+	(Gitlab #1542)
+
 Kea 1.8.1 (stable) released on Nov 12, 2020
 
 1801.   [build]         razvan
diff --git a/src/hooks/dhcp/lease_cmds/lease_cmds.cc b/src/hooks/dhcp/lease_cmds/lease_cmds.cc
index d11788c0ed..ac2bb32b30 100644
--- a/src/hooks/dhcp/lease_cmds/lease_cmds.cc
+++ b/src/hooks/dhcp/lease_cmds/lease_cmds.cc
@@ -1819,7 +1819,7 @@ LeaseCmdsImpl::lease4UpdateHandler(CalloutHandle& handle) {
                 // Try to avoid a race.
                 ResourceHandler4 resource_handler;
                 use_cs = !resource_handler.tryLock4(lease4->addr_);
-                if (use_cs) {
+                if (!use_cs) {
                     added = addOrUpdate4(lease4, force_create);
                 }
             }