diff --git a/NEWS b/NEWS
index 1a01c2711cb..3d66f3e9e2d 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ PHP                                                                        NEWS
 
 - FPM:
   . Fixed ACL build check on MacOS. (David Carlier)
+  . Fixed bug #72185: php-fpm writes empty fcgi record causing nginx 502.
+    (Jakub Zelenka, loveharmful)
 
 - SPL:
   . Fixed bug GH-8235 (iterator_count() may run indefinitely). (cmb)
diff --git a/main/fastcgi.c b/main/fastcgi.c
index e3acd9ac3a1..9eb504bae70 100644
--- a/main/fastcgi.c
+++ b/main/fastcgi.c
@@ -1590,10 +1590,10 @@ int fcgi_write(fcgi_request *req, fcgi_request_type type, const char *str, int l
 		memcpy(req->out_pos, str, len);
 		req->out_pos += len;
 	} else if (len - limit < (int)(sizeof(req->out_buf) - sizeof(fcgi_header))) {
-		if (!req->out_hdr) {
-			open_packet(req, type);
-		}
 		if (limit > 0) {
+			if (!req->out_hdr) {
+				open_packet(req, type);
+			}
 			memcpy(req->out_pos, str, limit);
 			req->out_pos += limit;
 		}
diff --git a/sapi/fpm/tests/bug72185-fcgi-empty-frame.phpt b/sapi/fpm/tests/bug72185-fcgi-empty-frame.phpt
new file mode 100644
index 00000000000..7c4b4468e35
--- /dev/null
+++ b/sapi/fpm/tests/bug72185-fcgi-empty-frame.phpt
@@ -0,0 +1,52 @@
+--TEST--
+FPM: bug72185 - FastCGI empty frame incorrectly created
+--SKIPIF--
+<?php include "skipif.inc"; ?>
+--FILE--
+<?php
+
+require_once "tester.inc";
+
+$cfg = <<<EOT
+[global]
+error_log = {{FILE:LOG}}
+[unconfined]
+listen = {{ADDR}}
+pm = dynamic
+pm.max_children = 2
+pm.start_servers = 1
+pm.min_spare_servers = 1
+pm.max_spare_servers = 2
+catch_workers_output = yes
+decorate_workers_output = no
+php_value[html_errors] = false
+EOT;
+
+$code = <<<'EOT'
+<?php
+for ($i=0; $i < 167; $i++) {
+    error_log('PHP is the best programming language');
+}
+echo 'end';
+EOT;
+
+$tester = new FPM\Tester($cfg, $code);
+$tester->start();
+$tester->expectLogStartNotices();
+$tester->request()->expectBody('end');
+for ($i=0; $i < 167; $i++) {
+    $tester->expectLogNotice("PHP message: PHP is the best programming language");
+}
+$tester->terminate();
+$tester->expectLogTerminatingNotices();
+$tester->close();
+
+?>
+Done
+--EXPECT--
+Done
+--CLEAN--
+<?php
+require_once "tester.inc";
+FPM\Tester::clean();
+?>
diff --git a/sapi/fpm/tests/fcgi.inc b/sapi/fpm/tests/fcgi.inc
index 0d16e5ba0ba..d17a659dd9c 100644
--- a/sapi/fpm/tests/fcgi.inc
+++ b/sapi/fpm/tests/fcgi.inc
@@ -555,6 +555,25 @@ class Client
         return $id;
     }
 
+    /**
+     * Append response data.
+     *
+     * @param $resp Response
+     * @param $type Either err or our
+     *
+     * @throws \Exception
+     */
+    private function fcgi_stream_append($resp, $type) {
+        if (isset($this->_requests[$resp['requestId']][$type . '_finished'])) {
+            throw new \Exception('FCGI_STD' . strtoupper($type) . ' stream already finished by empty record');
+        }
+        if ($resp['content'] === '') {
+            $this->_requests[$resp['requestId']][$type . '_finished'] = true;
+        } else {
+            $this->_requests[$resp['requestId']][$type . '_response'] .= $resp['content'];
+        }
+    }
+
     /**
      * Blocking call that waits for response data of the specific request
      *
@@ -593,13 +612,12 @@ class Client
             if ($resp['type'] == self::STDOUT || $resp['type'] == self::STDERR) {
                 if ($resp['type'] == self::STDERR) {
                     $this->_requests[$resp['requestId']]['state'] = self::REQ_STATE_ERR;
-                    $this->_requests[$resp['requestId']]['err_response'] .= $resp['content'];
+                    $this->fcgi_stream_append($resp, 'err');
                 } else {
-                    $this->_requests[$resp['requestId']]['out_response'] .= $resp['content'];
+                    $this->fcgi_stream_append($resp, 'out');
                 }
                 $this->_requests[$resp['requestId']]['response'] .= $resp['content'];
-            }
-            if ($resp['type'] == self::END_REQUEST) {
+            } elseif ($resp['type'] == self::END_REQUEST) {
                 $this->_requests[$resp['requestId']]['state'] = self::REQ_STATE_OK;
                 if ($resp['requestId'] == $requestId) {
                     break;
diff --git a/sapi/fpm/tests/logtool.inc b/sapi/fpm/tests/logtool.inc
index caf88ce662b..e085ae291be 100644
--- a/sapi/fpm/tests/logtool.inc
+++ b/sapi/fpm/tests/logtool.inc
@@ -364,7 +364,7 @@ class LogTool
         }
 
         $line = rtrim($line);
-        $pattern = sprintf('/^%s %s: %s$/', self::P_TIME, $type, $expectedMessage);
+        $pattern = sprintf('/^(%s )?%s: %s$/', self::P_TIME, $type, $expectedMessage);
 
         if (preg_match($pattern, $line, $matches) === 0) {
             return $this->error(