diff --git a/autosubmit/job/job_packages.py b/autosubmit/job/job_packages.py
index 309881657862c47ba21ed1bfabe6a48f395d0c6c..313f9cfa3a19c0fcec7cff8debd13237687868c3 100644
--- a/autosubmit/job/job_packages.py
+++ b/autosubmit/job/job_packages.py
@@ -54,7 +54,7 @@ def jobs_in_wrapper_str(as_conf, current_wrapper):
     else:
         jobs_in_wrapper = jobs_in_wrapper.split(" ")
     jobs_in_wrapper = [job.strip(" ,") for job in jobs_in_wrapper]
-    return "&".join(jobs_in_wrapper)
+    return "_".join(jobs_in_wrapper)
 class JobPackageBase(object):
     """
     Class to manage the package of jobs to be submitted by autosubmit
diff --git a/test/unit/test_job_package.py b/test/unit/test_job_package.py
index e70f1087225bd228027490c577a692f37dcd4e34..3808dba35bf988240d0511fadafb7da96b0ff546 100644
--- a/test/unit/test_job_package.py
+++ b/test/unit/test_job_package.py
@@ -4,6 +4,7 @@ import os
 from pathlib import Path
 import inspect
 import tempfile
+
 from mock import MagicMock, ANY
 from mock import patch
 
@@ -11,9 +12,11 @@ from autosubmit.job.job import Job
 from autosubmit.job.job_common import Status
 from autosubmit.job.job_list import JobList
 from autosubmit.job.job_list_persistence import JobListPersistenceDb
-from autosubmit.job.job_packages import JobPackageSimple, JobPackageVertical
+from autosubmit.job.job_packages import JobPackageSimple, JobPackageVertical, jobs_in_wrapper_str
 from autosubmitconfigparser.config.configcommon import AutosubmitConfig
 from autosubmitconfigparser.config.yamlparser import YAMLParserFactory
+import pytest
+from autosubmit.job.job_packages import jobs_in_wrapper_str
 
 
 class FakeBasicConfig:
@@ -206,3 +209,21 @@ class TestJobPackage(TestCase):
         self.job_package._create_scripts.is_called_once_with()
         self.job_package._send_files.is_called_once_with()
         self.job_package._do_submission.is_called_once_with()
+
+@pytest.fixture
+def mock_as_conf():
+    class MockAsConf:
+        experiment_data = {
+            "WRAPPERS": {
+                "current_wrapper": {
+                    "JOBS_IN_WRAPPER": "job1 job2 job3"
+                }
+            }
+        }
+    return MockAsConf()
+
+def test_jobs_in_wrapper_str(mock_as_conf):
+    # Arrange
+    current_wrapper = "current_wrapper"
+    result = jobs_in_wrapper_str(mock_as_conf, current_wrapper)
+    assert result == "job1_job2_job3"
\ No newline at end of file