diff --git a/addons/resource/models/resource_calendar.py b/addons/resource/models/resource_calendar.py
index a5aaad0cae8..1093dbc6ef1 100644
--- a/addons/resource/models/resource_calendar.py
+++ b/addons/resource/models/resource_calendar.py
@@ -488,7 +488,7 @@ class ResourceCalendar(models.Model):
             # take durations in days proportionally to what is left of the interval.
             interval_hours = (stop - start).total_seconds() / 3600
             day_hours[start.date()] += interval_hours
-            day_days[start.date()] += meta.duration_days * interval_hours / meta.duration_hours
+            day_days[start.date()] += sum(meta.mapped('duration_days')) * interval_hours / sum(meta.mapped('duration_hours'))
 
         return {
             # Round the number of days to the closest 16th of a day.
diff --git a/addons/test_resource/tests/common.py b/addons/test_resource/tests/common.py
index a4f28f07a6d..c8411481b76 100644
--- a/addons/test_resource/tests/common.py
+++ b/addons/test_resource/tests/common.py
@@ -61,6 +61,8 @@ class TestResourceCommon(TransactionCase):
 
         cls.calendar_paul = cls._define_calendar('Morning and evening shifts', sum([((2, 7, i, 0.5), (10, 16, i, 0.5)) for i in range(5)], ()), 'Brazil/DeNoronha')
 
+        cls.calendar_bob = cls._define_calendar('Calendar with adjacent attendances', sum([((8, 12, i, 0.5), (12, 16, i, 0.5)) for i in range(5)], ()), 'Europe/Brussels')
+
         # Employee is linked to a resource.resource via resource.mixin
         cls.jean = cls.env['resource.test'].create({
             'name': 'Jean',
@@ -84,6 +86,12 @@ class TestResourceCommon(TransactionCase):
             'resource_calendar_id': cls.calendar_paul.id,
         })
 
+        cls.bob = cls.env['resource.test'].create({
+            'name': 'Bob',
+            'resource_calendar_id': cls.calendar_bob.id,
+        })
+
+
         cls.two_weeks_resource = cls._define_calendar_2_weeks(
             'Two weeks resource',
             [
diff --git a/addons/test_resource/tests/test_resource.py b/addons/test_resource/tests/test_resource.py
index e114ef1b86e..82ff87dc67c 100644
--- a/addons/test_resource/tests/test_resource.py
+++ b/addons/test_resource/tests/test_resource.py
@@ -668,6 +668,14 @@ class TestResMixin(TestResourceCommon):
         )[self.jean.id]
         self.assertEqual(data, {'days': 5, 'hours': 40})
 
+        # Viewing it as Bob
+        data = self.bob._get_work_days_data_batch(
+            datetime_tz(2018, 4, 2, 0, 0, 0, tzinfo=self.bob.tz),
+            datetime_tz(2018, 4, 6, 16, 0, 0, tzinfo=self.bob.tz),
+        )[self.bob.id]
+        self.assertEqual(data, {'days': 5, 'hours': 40})
+
+
         # Viewing it as Patel
         # Views from 2018/04/01 20:00:00 to 2018/04/06 12:00:00
         data = self.jean._get_work_days_data_batch(