diff --git a/erpnext/support/doctype/issue/issue.py b/erpnext/support/doctype/issue/issue.py
index 22630d80f38..3ec23cf1481 100644
--- a/erpnext/support/doctype/issue/issue.py
+++ b/erpnext/support/doctype/issue/issue.py
@@ -312,7 +312,7 @@ def is_first_response(issue):
 
 
 def calculate_first_response_time(issue, first_responded_on):
-	issue_creation_date = issue.service_level_agreement_creation or issue.creation
+	issue_creation_date = get_datetime(issue.service_level_agreement_creation or issue.creation)
 	issue_creation_time = get_time_in_seconds(issue_creation_date)
 	first_responded_on_in_seconds = get_time_in_seconds(first_responded_on)
 	support_hours = frappe.get_cached_doc(
diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
index 26c017bddaa..6a39a434b6a 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
@@ -25,7 +25,7 @@ from frappe.utils.caching import redis_cache
 from frappe.utils.nestedset import get_ancestors_of
 from frappe.utils.safe_exec import get_safe_globals
 
-from erpnext.support.doctype.issue.issue import get_holidays
+from erpnext.support.doctype.issue.issue import calculate_first_response_time, get_holidays
 
 
 class ServiceLevelAgreement(Document):
@@ -552,6 +552,8 @@ def handle_status_change(doc, apply_sla_for_resolution):
 	def set_first_response():
 		if doc.meta.has_field("first_responded_on") and not doc.get("first_responded_on"):
 			doc.first_responded_on = now_time
+			if doc.meta.has_field("first_response_time"):
+				doc.first_response_time = calculate_first_response_time(doc, doc.first_responded_on)
 			if get_datetime(doc.get("first_responded_on")) > get_datetime(doc.get("response_by")):
 				record_assigned_users_on_failure(doc)