diff --git a/.github/actions/acc_test/action.yaml b/.github/actions/acc_test/action.yaml
index 26aaf210..1d643ac6 100644
--- a/.github/actions/acc_test/action.yaml
+++ b/.github/actions/acc_test/action.yaml
@@ -192,7 +192,7 @@ runs:
         TF_ACC_KEK_SERVICE_ACCOUNT=${TF_ACC_KEK_SERVICE_ACCOUNT} \
         go test ${{ inputs.test_file }} -count=1 -timeout=30m
       env:
-        TF_PROJECT_ID: ${{ inputs.project_id }}
+        TF_ACC_PROJECT_ID: ${{ inputs.project_id }}
         TF_ACC_REGION: ${{ inputs.region }}
         TF_ACC_TEST_PROJECT_USER_EMAIL: ${{ inputs.project_user_email }}
         TF_ACC_KEK_KEY_ID: ${{ inputs.tf_acc_kek_key_id }}
@@ -220,7 +220,7 @@ runs:
         TF_ACC_KEK_SERVICE_ACCOUNT=${TF_ACC_KEK_SERVICE_ACCOUNT} \
         go test ./... -count=1 -timeout=30m
       env:
-        TF_PROJECT_ID: ${{ inputs.project_id }}
+        TF_ACC_PROJECT_ID: ${{ inputs.project_id }}
         TF_ACC_REGION: ${{ inputs.region }}
         TF_ACC_TEST_PROJECT_USER_EMAIL: ${{ inputs.project_user_email }}
         TF_ACC_KEK_KEY_ID: ${{ inputs.tf_acc_kek_key_id }}
diff --git a/.github/workflows/tf-acc-test.yaml b/.github/workflows/tf-acc-test.yaml
index 890c085a..c56056a2 100644
--- a/.github/workflows/tf-acc-test.yaml
+++ b/.github/workflows/tf-acc-test.yaml
@@ -18,7 +18,7 @@ jobs:
         uses: ./.github/actions/acc_test
         with:
           go-version: ${{ env.GO_VERSION }}
-          project_id: ${{ vars.TEST_PROJECT_ID }}
+          project_id: ${{ vars.TF_ACC_PROJECT_ID }}
           region: 'eu01'
           service_account_json_content_b64: "${{ secrets.TF_ACC_SERVICE_ACCOUNT_JSON_B64 }}"
           project_user_email: ${{ vars.TEST_PROJECT_USER_EMAIL }}
diff --git a/stackit/internal/services/postgresflexalpha/instance/resource.go b/stackit/internal/services/postgresflexalpha/instance/resource.go
index b4bfe2bc..d07bf546 100644
--- a/stackit/internal/services/postgresflexalpha/instance/resource.go
+++ b/stackit/internal/services/postgresflexalpha/instance/resource.go
@@ -196,9 +196,9 @@ func (r *instanceResource) Create(
 
 	ctx = core.InitProviderContext(ctx)
 
-	projectId := model.ProjectId.ValueString()
+	projectID := model.ProjectId.ValueString()
 	region := model.Region.ValueString()
-	ctx = tflog.SetField(ctx, "project_id", projectId)
+	ctx = tflog.SetField(ctx, "project_id", projectID)
 	ctx = tflog.SetField(ctx, "region", region)
 
 	var netAcl []string
@@ -214,7 +214,7 @@ func (r *instanceResource) Create(
 	// Create new instance
 	createResp, err := r.client.DefaultAPI.CreateInstanceRequest(
 		ctx,
-		projectId,
+		projectID,
 		region,
 	).CreateInstanceRequestPayload(payload).Execute()
 	if err != nil {
@@ -231,7 +231,7 @@ func (r *instanceResource) Create(
 
 	// Set data returned by API in identity
 	identity := InstanceResourceIdentityModel{
-		ProjectID:  types.StringValue(projectId),
+		ProjectID:  types.StringValue(projectID),
 		Region:     types.StringValue(region),
 		InstanceID: types.StringPointerValue(instanceID),
 	}
@@ -240,7 +240,7 @@ func (r *instanceResource) Create(
 		return
 	}
 
-	waitResp, err := wait.CreateInstanceWaitHandler(ctx, r.client.DefaultAPI, projectId, region, *instanceID).
+	waitResp, err := wait.CreateInstanceWaitHandler(ctx, r.client.DefaultAPI, projectID, region, *instanceID).
 		WaitWithContext(ctx)
 	if err != nil {
 		core.LogAndAddError(
diff --git a/stackit/internal/services/postgresflexalpha/postgresflex_acc_test.go b/stackit/internal/services/postgresflexalpha/postgresflex_acc_test.go
index 64b7e901..0b59be64 100644
--- a/stackit/internal/services/postgresflexalpha/postgresflex_acc_test.go
+++ b/stackit/internal/services/postgresflexalpha/postgresflex_acc_test.go
@@ -297,6 +297,9 @@ func TestAccInstanceWithUsers(t *testing.T) {
 	data := getExample()
 
 	userName := "testUser"
+	if pID, ok := os.LookupEnv("TF_ACC_PROJECT_ID"); !ok || pID == "" {
+		t.Errorf("TF_ACC_PROJECT_ID is not set")
+	}
 	data.Users = []User{
 		{
 			Name:      userName,