diff --git a/script/ci-set-timestamps b/script/ci-set-timestamps
index d0812497..425a55ec 100755
--- a/script/ci-set-timestamps
+++ b/script/ci-set-timestamps
@@ -1,5 +1,5 @@
 #!/bin/sh
 
-BUILD_TIMESTAMP=`date -d $CI_COMMIT_TIMESTAMP "CCYYMMDDhhmm.SS"`
+BUILD_TIMESTAMP=`date -d $CI_COMMIT_TIMESTAMP "+CCYYMMDDhhmm.SS"`
 
 touch -t $BUILD_TIMESTAMP apps/**/*.ex apps/**/*.exs config/**/*.ex config/**/*.exs mix.exs