diff --git a/erpnext/projects/doctype/project/project.py b/erpnext/projects/doctype/project/project.py
index cc04ea2289..b1a11398c2 100644
--- a/erpnext/projects/doctype/project/project.py
+++ b/erpnext/projects/doctype/project/project.py
@@ -60,7 +60,6 @@ class Project(Document):
 		self.validate_weights()
 		self.sync_tasks()
 		self.tasks = []
-		self.load_tasks()
 		self.send_welcome_email()
 
 	def validate_project_name(self):
@@ -82,6 +81,9 @@ class Project(Document):
 
 	def sync_tasks(self):
 		"""sync tasks and remove table"""
+		if not hasattr(self, "deleted_task_list"):
+			self.set("deleted_task_list", [])
+
 		if self.flags.dont_sync_tasks: return
 		task_names = []
 
@@ -130,7 +132,7 @@ class Project(Document):
 
 		# delete
 		for t in frappe.get_all("Task", ["name"], {"project": self.name, "name": ("not in", task_names)}):
-			frappe.delete_doc("Task", t.name)
+			self.deleted_task_list.append(t.name)
 
 	def update_costing_and_percentage_complete(self):
 		self.update_percent_complete()
@@ -139,8 +141,14 @@ class Project(Document):
 	def is_row_updated(self, row, existing_task_data):
 		if self.get("__islocal") or not existing_task_data: return True
 
+		project_task_custom_fields = frappe.get_all("Custom Field", {"dt": "Project Task"}, "fieldname")
+
 		d = existing_task_data.get(row.task_id)
 
+		for field in project_task_custom_fields:
+			if row.get(field) != d.get(field):
+				return True
+
 		if (d and (row.title != d.title or row.status != d.status
 			or getdate(row.start_date) != getdate(d.start_date) or getdate(row.end_date) != getdate(d.end_date)
 			or row.description != d.description or row.task_weight != d.task_weight)):
@@ -263,9 +271,19 @@ class Project(Document):
 				user.welcome_email_sent=1
 
 	def on_update(self):
+		self.delete_task()
+		self.load_tasks()
 		self.update_costing_and_percentage_complete()
 		self.update_dependencies_on_duplicated_project()
 
+	def delete_task(self):
+		if not self.get('deleted_task_list'): return
+
+		for d in self.get('deleted_task_list'):
+			frappe.delete_doc("Task", d)
+
+		self.deleted_task_list = []
+
 	def update_dependencies_on_duplicated_project(self):
 		if self.flags.dont_sync_tasks: return
 		if not self.copied_from: