diff --git a/drivers/place/survey_mailer.cr b/drivers/place/survey_mailer.cr
index d46fc88307f..c33eff5e6e9 100644
--- a/drivers/place/survey_mailer.cr
+++ b/drivers/place/survey_mailer.cr
@@ -45,10 +45,13 @@ class Place::SurveyMailer < PlaceOS::Driver
 
   @[Security(Level::Support)]
   def send_survey_emails
-    invites = Array(SurveyInvite).from_json staff_api.get_survey_invites(sent: false).get.to_json
+    # using #get_survey_invites instead of #get_survey_invites(sent: false)
+    # due to `sent <> true` not being equivalent to `sent IS NOT true` in PostgreSQL
+    invites = Array(SurveyInvite).from_json staff_api.get_survey_invites.get.to_json
     sent_invites : Hash(String, Array(Int64)) = {} of String => Array(Int64)
 
     invites.each do |invite|
+      next if invite.sent
       begin
         if !(sent_surveys = sent_invites[invite.email]?) || !sent_surveys.includes?(invite.survey_id)
           sent_invites[invite.email] ||= [] of Int64
@@ -78,6 +81,6 @@ class Place::SurveyMailer < PlaceOS::Driver
     property survey_id : Int64
     property token : String
     property email : String
-    property sent : Bool
+    property sent : Bool?
   end
 end
diff --git a/drivers/place/survey_mailer_spec.cr b/drivers/place/survey_mailer_spec.cr
index 23ca1963d3d..53ae1065eac 100644
--- a/drivers/place/survey_mailer_spec.cr
+++ b/drivers/place/survey_mailer_spec.cr
@@ -5,7 +5,7 @@ class StaffAPI < DriverSpecs::MockDriver
   def get_survey_invites(survey_id : Int64? = nil, sent : Bool? = nil)
     survey_id ||= 1
 
-    unsent_invites = [
+    invites = [
       {
         id:        1,
         survey_id: survey_id,
@@ -21,15 +21,29 @@ class StaffAPI < DriverSpecs::MockDriver
         sent:      false,
       },
       {
-        id:        2,
+        id:        3,
         survey_id: survey_id,
         token:     "QWERTY",
         email:     "user2@spec.test",
         sent:      false,
       },
+      {
+        id:        4,
+        survey_id: survey_id,
+        token:     "QWERTY",
+        email:     "user3@spec.test",
+        sent:      nil,
+      },
+      {
+        id:        5,
+        survey_id: survey_id,
+        token:     "QWERTY",
+        email:     "user4@spec.test",
+        sent:      true,
+      },
     ]
 
-    JSON.parse(unsent_invites.to_json)
+    JSON.parse(invites.to_json)
   end
 
   def update_survey_invite(token : String, email : String? = nil, sent : Bool? = nil)
@@ -79,5 +93,5 @@ DriverSpecs.mock_driver "Place::StaffAPI" do
   })
 
   _resp = exec(:send_survey_emails).get
-  system(:Mailer_1)[:sent].should eq 2
+  system(:Mailer_1)[:sent].should eq 3
 end