diff --git a/CHANGES.rst b/CHANGES.rst
index 514e9d1d79..64d38ab898 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,14 @@
 Changelog
 =========
 
+1.3.5 (unreleased)
+------------------
+
+**Fixed**
+
+- #1617 Fix writing methods on read when reindexing services
+
+
 1.3.4 (2020-08-11)
 ------------------
 
diff --git a/bika/lims/content/analysisservice.py b/bika/lims/content/analysisservice.py
index 9ac730b41a..20dc9e75d7 100644
--- a/bika/lims/content/analysisservice.py
+++ b/bika/lims/content/analysisservice.py
@@ -496,7 +496,8 @@ def getAvailableMethodUIDs(self):
         Returns the UIDs of the available methods. it is used as a
         vocabulary to fill the selection list of 'Methods' field.
         """
-        method_uids = self.getRawMethods()
+        # N.B. we return a copy of the list to avoid accidental writes
+        method_uids = self.getRawMethods()[:]
         if self.getInstrumentEntryOfResults():
             for instrument in self.getInstruments():
                 method_uids.extend(instrument.getRawMethods())
diff --git a/bika/lims/upgrade/configure.zcml b/bika/lims/upgrade/configure.zcml
index 4e56ee73c3..06a0368cb3 100644
--- a/bika/lims/upgrade/configure.zcml
+++ b/bika/lims/upgrade/configure.zcml
@@ -199,4 +199,11 @@
        handler="bika.lims.upgrade.v01_03_004.upgrade"
        profile="bika.lims:default"/>
 
+   <genericsetup:upgradeStep
+       title="Upgrade to SENAITE.CORE 1.3.5"
+       source="1.3.4"
+       destination="1.3.5"
+       handler="bika.lims.upgrade.v01_03_005.upgrade"
+       profile="bika.lims:default"/>
+
 </configure>
diff --git a/bika/lims/upgrade/v01_03_005.py b/bika/lims/upgrade/v01_03_005.py
new file mode 100644
index 0000000000..b964930b68
--- /dev/null
+++ b/bika/lims/upgrade/v01_03_005.py
@@ -0,0 +1,76 @@
+# -*- coding: utf-8 -*-
+#
+# This file is part of SENAITE.CORE.
+#
+# SENAITE.CORE is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation, version 2.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 51
+# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# Copyright 2018-2020 by it's authors.
+# Some rights reserved, see README and LICENSE.
+
+from bika.lims import api
+from bika.lims import logger
+from bika.lims.catalog import CATALOG_ANALYSIS_REQUEST_LISTING
+from bika.lims.catalog import SETUP_CATALOG
+from bika.lims.config import PROJECTNAME as product
+from bika.lims.upgrade import upgradestep
+from bika.lims.upgrade.utils import UpgradeUtils
+
+version = "1.3.5"  # Remember version number in metadata.xml and setup.py
+profile = "profile-{0}:default".format(product)
+
+
+@upgradestep(product, version)
+def upgrade(tool):
+    portal = tool.aq_inner.aq_parent
+    setup = portal.portal_setup
+    ut = UpgradeUtils(portal)
+    ver_from = ut.getInstalledVersion(product)
+
+    if ut.isOlderVersion(product, version):
+        logger.info("Skipping upgrade of {0}: {1} > {2}".format(
+            product, ver_from, version))
+        return True
+
+    logger.info("Upgrading {0}: {1} -> {2}".format(product, ver_from, version))
+
+    # -------- ADD YOUR STUFF BELOW --------
+
+    # Fix writing methods on read when reindexing services
+    # https://github.com/senaite/senaite.core/pull/1617
+    remove_duplicate_methods_in_services(portal)
+
+    logger.info("{0} upgraded to version {1}".format(product, version))
+    return True
+
+
+def remove_duplicate_methods_in_services(portal):
+    """A bug caused duplicate methods stored in services which need to be fixed
+    """
+    logger.info("Remove duplicate methods from services...")
+
+    cat = api.get_tool(SETUP_CATALOG)
+    services = cat({"portal_type": "AnalysisService"})
+    total = len(services)
+
+    for num, service in enumerate(services):
+        if num and num % 10 == 0:
+            logger.info("Processed {}/{} Services".format(num, total))
+        obj = api.get_object(service)
+        methods = list(set(obj.getRawMethods()))
+        if not methods:
+            continue
+        obj.setMethods(methods)
+        obj.reindexObject()
+
+    logger.info("Remove duplicate methods from services [DONE]")
diff --git a/setup.py b/setup.py
index 3645a40d11..75dd088be3 100644
--- a/setup.py
+++ b/setup.py
@@ -20,7 +20,7 @@
 
 from setuptools import setup, find_packages
 
-version = '1.3.4'
+version = '1.3.5'
 
 setup(
     name='senaite.core',