diff --git a/jenkins/ci-pipelines/ci_stage_2.groovy b/jenkins/ci-pipelines/ci_stage_2.groovy
index a6dcfa4..0691dcc 100644
--- a/jenkins/ci-pipelines/ci_stage_2.groovy
+++ b/jenkins/ci-pipelines/ci_stage_2.groovy
@@ -147,9 +147,14 @@
         for (charmPath in charms) {
             def directory = charmPath
             if (fileExists("$charmPath/charmcraft.yaml")) {
-                CHECK_CHANGES = "git diff --name-only origin/$GERRIT_BRANCH -- $directory |wc -l"
+                if (isMergeJob) {
+                    CHECK_CHANGES = "git diff --name-only HEAD^1 -- $directory |wc -l"
+                } else {
+                    CHECK_CHANGES = "git diff --name-only origin/$GERRIT_BRANCH -- $directory |wc -l"
+                }
                 charmsChanged = sh(returnStdout:true,  script: CHECK_CHANGES).trim()
-                if (charmsChanged != "0" || isMergeJob) {
+
+                if (charmsChanged != "0") {
                     println("$directory has changes, rebuilding")
 
                     parallelSteps[directory] = {