diff --git a/pkg/models/task_collection_subtasks_move_test.go b/pkg/models/task_collection_subtasks_move_test.go
new file mode 100644
index 000000000..0b30bb469
--- /dev/null
+++ b/pkg/models/task_collection_subtasks_move_test.go
@@ -0,0 +1,80 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// 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 Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package models
+
+import (
+	"testing"
+
+	"code.vikunja.io/api/pkg/db"
+	"code.vikunja.io/api/pkg/user"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTaskCollection_SubtaskRemainsAfterMove(t *testing.T) {
+	db.LoadAndAssertFixtures(t)
+	s := db.NewSession()
+	defer s.Close()
+
+	u := &user.User{ID: 1}
+
+	c := &TaskCollection{
+		ProjectID: 1,
+		Expand:    []TaskCollectionExpandable{TaskCollectionExpandSubtasks},
+	}
+
+	res, _, _, err := c.ReadAll(s, u, "", 0, 50)
+	require.NoError(t, err)
+	tasks, ok := res.([]*Task)
+	require.True(t, ok)
+
+	found := false
+	for _, tsk := range tasks {
+		if tsk.ID == 29 {
+			found = true
+			break
+		}
+	}
+	assert.True(t, found, "subtask should be returned before moving")
+
+	subtask := &Task{ID: 29, ProjectID: 7}
+	err = subtask.Update(s, u)
+	require.NoError(t, err)
+	require.NoError(t, s.Commit())
+
+	s2 := db.NewSession()
+	defer s2.Close()
+	c = &TaskCollection{
+		ProjectID: 7,
+		Expand:    []TaskCollectionExpandable{TaskCollectionExpandSubtasks},
+	}
+
+	res, _, _, err = c.ReadAll(s2, u, "", 0, 50)
+	require.NoError(t, err)
+	tasks, ok = res.([]*Task)
+	require.True(t, ok)
+
+	found = false
+	for _, tsk := range tasks {
+		if tsk.ID == 29 {
+			found = true
+			break
+		}
+	}
+	assert.True(t, found, "subtask should be returned after moving to another project")
+}
diff --git a/pkg/models/task_search.go b/pkg/models/task_search.go
index a8baf3280..07aec884f 100644
--- a/pkg/models/task_search.go
+++ b/pkg/models/task_search.go
@@ -294,7 +294,7 @@ func (d *dbTaskSearcher) Search(opts *taskSearchOptions) (tasks []*Task, totalCo
 	var projectIDCond builder.Cond
 	var favoritesCond builder.Cond
 	if len(opts.projectIDs) > 0 {
-		projectIDCond = builder.In("project_id", opts.projectIDs)
+		projectIDCond = builder.In("tasks.project_id", opts.projectIDs)
 	}
 
 	if d.hasFavoritesProject {
@@ -328,7 +328,10 @@ func (d *dbTaskSearcher) Search(opts *taskSearchOptions) (tasks []*Task, totalCo
 	}
 
 	if expandSubtasks {
-		cond = builder.And(cond, builder.IsNull{"task_relations.id"})
+		cond = builder.And(cond, builder.Or(
+			builder.IsNull{"task_relations.id"},
+			builder.Expr("parent_tasks.project_id != tasks.project_id"),
+		))
 	}
 
 	query := d.s.
@@ -349,7 +352,9 @@ func (d *dbTaskSearcher) Search(opts *taskSearchOptions) (tasks []*Task, totalCo
 		query = query.Join("LEFT", "task_buckets", "task_buckets.task_id = tasks.id")
 	}
 	if expandSubtasks {
-		query = query.Join("LEFT", "task_relations", "tasks.id = task_relations.task_id and task_relations.relation_kind = 'parenttask'")
+		query = query.
+			Join("LEFT", "task_relations", "tasks.id = task_relations.task_id and task_relations.relation_kind = 'parenttask'").
+			Join("LEFT", "tasks parent_tasks", "task_relations.other_task_id = parent_tasks.id")
 	}
 
 	tasks = []*Task{}
@@ -416,7 +421,9 @@ func (d *dbTaskSearcher) Search(opts *taskSearchOptions) (tasks []*Task, totalCo
 		queryCount = queryCount.Join("LEFT", "task_buckets", "task_buckets.task_id = tasks.id")
 	}
 	if expandSubtasks {
-		queryCount = queryCount.Join("LEFT", "task_relations", "tasks.id = task_relations.task_id and task_relations.relation_kind = 'parenttask'")
+		queryCount = queryCount.
+			Join("LEFT", "task_relations", "tasks.id = task_relations.task_id and task_relations.relation_kind = 'parenttask'").
+			Join("LEFT", "tasks parent_tasks", "task_relations.other_task_id = parent_tasks.id")
 	}
 	totalCount, err = queryCount.
 		Select("count(DISTINCT tasks.id)").