diff --git a/addons/mail/static/src/components/rtc_option_list/rtc_option_list.xml b/addons/mail/static/src/components/rtc_option_list/rtc_option_list.xml
index a45c0e9a922..9bdd00765bf 100644
--- a/addons/mail/static/src/components/rtc_option_list/rtc_option_list.xml
+++ b/addons/mail/static/src/components/rtc_option_list/rtc_option_list.xml
@@ -24,7 +24,7 @@
                     <i class="o_RtcOptionList_buttonIcon fa fa-lg fa-cog"/>
                     <span class="o_RtcOptionList_buttonText">Settings</span>
                 </button>
-                <t t-if="env.isDebug()">
+                <t t-if="messaging.modelManager.isDebug">
                     <button class="o_RtcOptionList_button" t-on-click="rtcOptionList.onClickDownloadLogs">
                         <i class="o_RtcOptionList_buttonIcon fa fa-lg fa-file-text-o"/>
                         <span class="o_RtcOptionList_buttonText">Download logs</span>
diff --git a/addons/mail/static/src/model/model_field.js b/addons/mail/static/src/model/model_field.js
index 6fe7514166b..5e3930e22fe 100644
--- a/addons/mail/static/src/model/model_field.js
+++ b/addons/mail/static/src/model/model_field.js
@@ -569,7 +569,8 @@ export class ModelField {
      * @returns {boolean} whether the value changed for the current field
      */
     _setRelationLinkX2Many(record, newValue, { hasToUpdateInverse = true } = {}) {
-        const recordsToLink = this._convertX2ManyValue(newValue);
+        const hasToVerify = record.modelManager.isDebug;
+        const recordsToLink = this._convertX2ManyValue(newValue, { hasToVerify });
         const otherRecords = this.read(record);
 
         let hasChanged = false;
@@ -607,7 +608,9 @@ export class ModelField {
      * @returns {boolean} whether the value changed for the current field
      */
     _setRelationLinkX2One(record, recordToLink, { hasToUpdateInverse = true } = {}) {
-        this._verifyRelationalValue(recordToLink);
+        if (record.modelManager.isDebug) {
+            this._verifyRelationalValue(recordToLink);
+        }
         const prevOtherRecord = this.read(record);
         // other record already linked, avoid linking twice
         if (prevOtherRecord === recordToLink) {
@@ -648,7 +651,8 @@ export class ModelField {
         let hasToReorder = false;
         const otherRecordsSet = this.read(record);
         const otherRecordsList = [...otherRecordsSet];
-        const recordsToReplaceList = [...this._convertX2ManyValue(newValue)];
+        const hasToVerify = record.modelManager.isDebug;
+        const recordsToReplaceList = [...this._convertX2ManyValue(newValue, { hasToVerify })];
         const recordsToReplaceSet = new Set(recordsToReplaceList);
 
         // records to link
diff --git a/addons/mail/static/src/model/model_manager.js b/addons/mail/static/src/model/model_manager.js
index 119c699ef69..9e1a8e2cb0e 100644
--- a/addons/mail/static/src/model/model_manager.js
+++ b/addons/mail/static/src/model/model_manager.js
@@ -98,6 +98,12 @@ export class ModelManager {
          * and for which required fields check still has to be executed.
          */
         this._updatedRecordsCheckRequired = new Set();
+        /**
+         * Determines whether this model manager should run in debug mode. Debug
+         * mode adds more integrity checks and more verbose error messages, at
+         * the cost of performance.
+         */
+        this.isDebug = false;
     }
 
     /**
@@ -247,9 +253,11 @@ export class ModelManager {
         if (!localId) {
             return;
         }
-        const modelName = localId.split('(')[0];
-        if (!isCheckingInheritance && modelName !== Model.name) {
-            throw Error(`wrong format of localId ${localId} for ${Model}.`);
+        if (!isCheckingInheritance && this.isDebug) {
+            const modelName = localId.split('(')[0];
+            if (modelName !== Model.name) {
+                throw Error(`wrong format of localId ${localId} for ${Model}.`);
+            }
         }
         for (const listener of this._listeners) {
             listener.lastObservedLocalIds.add(localId);
@@ -667,7 +675,7 @@ export class ModelManager {
             // Field values of record.
             __values: {},
         });
-        const record = !this.env.isDebug() ? nonProxyRecord : new Proxy(nonProxyRecord, {
+        const record = !this.isDebug ? nonProxyRecord : new Proxy(nonProxyRecord, {
             get: function getFromProxy(record, prop) {
                 if (
                     !Model.__fieldMap[prop] &&
diff --git a/addons/mail/static/src/models/rtc/rtc.js b/addons/mail/static/src/models/rtc/rtc.js
index a6b70cbab39..e54622e181d 100644
--- a/addons/mail/static/src/models/rtc/rtc.js
+++ b/addons/mail/static/src/models/rtc/rtc.js
@@ -357,7 +357,7 @@ registerModel({
          * @param {String} [param2.state] current state of the connection
          */
         _addLogEntry(token, entry, { error, step, state } = {}) {
-            if (!this.env.isDebug()) {
+            if (!this.modelManager.isDebug) {
                 return;
             }
             if (!(token in this.logs)) {
diff --git a/addons/mail/static/src/utils/test_utils.js b/addons/mail/static/src/utils/test_utils.js
index 49b3fed668e..959ec5d22a1 100644
--- a/addons/mail/static/src/utils/test_utils.js
+++ b/addons/mail/static/src/utils/test_utils.js
@@ -643,6 +643,14 @@ async function start(param0 = {}) {
                 loadingBaseDelayDuration,
                 messagingBus,
             },
+            /**
+             * Override to ensure tests run in debug mode to catch all potential
+             * programming errors and provide better message when they happen.
+             */
+            init(...args) {
+                this._super(...args);
+                this.modelManager.isDebug = true;
+            },
             /**
              * Override:
              * - to ensure the test setup is complete before starting otherwise