diff --git a/command/agent/config.go b/command/agent/config.go
index 0abd04fa2d..f009e1e2da 100644
--- a/command/agent/config.go
+++ b/command/agent/config.go
@@ -553,7 +553,7 @@ func MergeConfig(a, b *Config) *Config {
 	if b.DNSConfig.MaxStale != 0 {
 		result.DNSConfig.MaxStale = b.DNSConfig.MaxStale
 	}
-	if b.CheckUpdateIntervalRaw != "" {
+	if b.CheckUpdateIntervalRaw != "" || b.CheckUpdateInterval != 0 {
 		result.CheckUpdateInterval = b.CheckUpdateInterval
 	}