diff --git a/addons/web/static/src/js/fields/relational_fields.js b/addons/web/static/src/js/fields/relational_fields.js
index 4c92c0973b9..a1efa85498e 100644
--- a/addons/web/static/src/js/fields/relational_fields.js
+++ b/addons/web/static/src/js/fields/relational_fields.js
@@ -1221,18 +1221,14 @@ var FieldX2Many = AbstractField.extend({
     _onSaveLine: function (ev) {
         var self = this;
         ev.stopPropagation();
-        this.trigger_up('mutexify', {
-            action: function () {
-                return self.renderer.commitChanges(ev.data.recordID).then(function () {
-                    self.trigger_up('mutexify', {
-                        action: function () {
-                            return self._saveLine(ev.data.recordID)
-                                .done(ev.data.onSuccess)
-                                .fail(ev.data.onFailure);
-                        },
-                    });
-                });
-            },
+        this.renderer.commitChanges(ev.data.recordID).then(function () {
+            self.trigger_up('mutexify', {
+                action: function () {
+                    return self._saveLine(ev.data.recordID)
+                        .done(ev.data.onSuccess)
+                        .fail(ev.data.onFailure);
+                },
+            });
         });
     },
     /**
diff --git a/addons/web/static/tests/fields/relational_fields_tests.js b/addons/web/static/tests/fields/relational_fields_tests.js
index 2fff96e8ee3..8809d219e49 100644
--- a/addons/web/static/tests/fields/relational_fields_tests.js
+++ b/addons/web/static/tests/fields/relational_fields_tests.js
@@ -10331,6 +10331,56 @@ QUnit.module('relational_fields', {
         form.destroy();
     });
 
+    QUnit.test('no deadlock when leaving a one2many line with uncommitted changes', function (assert) {
+        // Before unselecting a o2m line, field widgets are asked to commit their changes (new values
+        // that they wouldn't have sent to the model yet). This test is added alongside a bug fix
+        // ensuring that we don't end up in a deadlock when a widget actually has some changes to
+        // commit at that moment.
+        assert.expect(9);
+         var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form>' +
+                    '<field name="turtles">' +
+                        '<tree editable="bottom">' +
+                            '<field name="turtle_foo"/>' +
+                        '</tree>' +
+                    '</field>' +
+                '</form>',
+            mockRPC: function (route, args) {
+                assert.step(args.method);
+                return this._super.apply(this, arguments);
+            },
+             // we set a fieldDebounce to precisely mock the behavior of the webclient: changes are
+             // not sent to the model at keystrokes, but when the input is left
+            fieldDebounce: 5000,
+        });
+
+        form.$('.o_field_x2many_list_row_add a').click();
+
+        form.$('input').val('some foo value').trigger('input');
+
+        // click to add a second row to unselect the current one, then save
+        form.$('.o_field_x2many_list_row_add a').click();
+        form.$buttons.find('.o_form_button_save').click();
+
+        assert.strictEqual(form.$('.o_form_readonly').length, 1,
+            "form view should be in readonly");
+        assert.strictEqual(form.$('.o_data_row').text(), 'some foo value',
+            "foo field should have correct value");
+        assert.verifySteps([
+            'default_get', // main record
+            'default_get', // line 1
+            'default_get', // line 2
+            'create',
+            'read', // main record
+            'read', // line 1
+        ]);
+
+        form.destroy();
+    });
+
     QUnit.module('FieldMany2Many');
 
     QUnit.test('many2many kanban: edition', function (assert) {