diff --git a/sao/src/common.js b/sao/src/common.js
index 5c88c69472..ea8b696e01 100644
--- a/sao/src/common.js
+++ b/sao/src/common.js
@@ -2765,18 +2765,18 @@
             if ((domain instanceof Array) &&
                     (domain.length == 1)) {
                 let [name, operator, value, ...model] = domain[0];
-                if (operator == '=' ||
-                    (single_value && operator == 'in' && value.length == 1)) {
+                const count = name.split('.').length - 1;
+                if (
+                    (operator == '=' ||
+                        (single_value && operator == 'in' && value.length == 1)) &&
+                    (!count ||
+                        ((count === 1) && model.length && name.endsWith('.id')))) {
                     value = operator == '=' ? value : value[0];
-                    var count = 0;
                     if (model.length && name.endsWith('.id')) {
-                        count = 1;
                         model = model[0];
                         value = [model, value];
                     }
-                    if ((name.split('.').length - 1) == count) {
-                        return [true, name, value];
-                    }
+                    return [true, name, value];
                 }
             }
             return [false, null, null];
diff --git a/sao/tests/sao.js b/sao/tests/sao.js
index 25f85b4fca..7d5c87ae09 100644
--- a/sao/tests/sao.js
+++ b/sao/tests/sao.js
@@ -2814,6 +2814,7 @@
         QUnit.ok(compare(unique_value(domain), [true, 'a.id', ['model', 1]]));
         domain = [['a.b.id', '=', 1, 'model']];
         QUnit.ok(compare(unique_value(domain), [false, null, null]));
+        QUnit.ok(compare(unique_value(domain, false), [false, null, null]));
         domain = [['a', 'in', [1]]];
         QUnit.ok(compare(unique_value(domain), [true, 'a', 1]));
         QUnit.ok(compare(unique_value(domain, false), [false, null, null]));
@@ -2825,6 +2826,7 @@
         QUnit.ok(compare(unique_value(domain), [false, null, null]));
         domain = [['a.id', 'in', [1], 'model']];
         QUnit.ok(compare(unique_value(domain), [true, 'a.id', ['model', 1]]));
+        QUnit.ok(compare(unique_value(domain, false), [false, null, null]));
     });
 
     QUnit.test('DomainInversion evaldomain', function() {
diff --git a/tryton/tryton/common/domain_inversion.py b/tryton/tryton/common/domain_inversion.py
index 02c7232a99..efbf0735c0 100644
--- a/tryton/tryton/common/domain_inversion.py
+++ b/tryton/tryton/common/domain_inversion.py
@@ -426,16 +426,18 @@ def unique_value(domain, single_value=True):
     if (isinstance(domain, list)
             and len(domain) == 1):
         name, operator, value, *model = domain[0]
-        if (operator == '='
-                or (single_value and operator == 'in' and len(value) == 1)):
+        count = name.count('.')
+        if (
+                (operator == '='
+                    or (single_value
+                        and operator == 'in' and len(value) == 1))
+                and (not count
+                    or (count == 1 and model and name.endswith('.id')))):
             value = value if operator == '=' and single_value else value[0]
-            count = 0
             if model and name.endswith('.id'):
-                count = 1
                 model = model[0]
                 value = [model, value]
-            if name.count('.') == count:
-                return True, name, value
+            return True, name, value
     return False, None, None
 
 
diff --git a/trytond/trytond/tests/test_tools.py b/trytond/trytond/tests/test_tools.py
index c2ae439f52..b4d843203f 100644
--- a/trytond/trytond/tests/test_tools.py
+++ b/trytond/trytond/tests/test_tools.py
@@ -846,6 +846,8 @@ class DomainInversionTestCase(unittest.TestCase):
 
         domain = [['a.b.id', '=', 1, 'model']]
         self.assertEqual(unique_value(domain), (False, None, None))
+        self.assertEqual(
+            unique_value(domain, single_value=False), (False, None, None))
 
         domain = [['a', 'in', [1]]]
         self.assertEqual(unique_value(domain), (True, 'a', 1))
@@ -863,6 +865,8 @@ class DomainInversionTestCase(unittest.TestCase):
 
         domain = [['a.id', 'in', [1], 'model']]
         self.assertEqual(unique_value(domain), (True, 'a.id', ['model', 1]))
+        self.assertEqual(
+            unique_value(domain, single_value=False), (False, None, None))
 
     def test_evaldomain(self):
         domain = [['x', '>', 5]]
diff --git a/trytond/trytond/tools/domain_inversion.py b/trytond/trytond/tools/domain_inversion.py
index 46926d0fc5..efbf0735c0 100644
--- a/trytond/trytond/tools/domain_inversion.py
+++ b/trytond/trytond/tools/domain_inversion.py
@@ -426,16 +426,18 @@ def unique_value(domain, single_value=True):
     if (isinstance(domain, list)
             and len(domain) == 1):
         name, operator, value, *model = domain[0]
-        if (operator == '='
-                or (single_value and operator == 'in' and len(value) == 1)):
-            value = value if operator == '=' else value[0]
-            count = 0
+        count = name.count('.')
+        if (
+                (operator == '='
+                    or (single_value
+                        and operator == 'in' and len(value) == 1))
+                and (not count
+                    or (count == 1 and model and name.endswith('.id')))):
+            value = value if operator == '=' and single_value else value[0]
             if model and name.endswith('.id'):
-                count = 1
                 model = model[0]
                 value = [model, value]
-            if name.count('.') == count:
-                return True, name, value
+            return True, name, value
     return False, None, None