Amazon s3 php errors from core

Hi,

I am getting the following php error pop up across different Perch Runway projects that use Amazon s3.

Array
(
    [type] => 2
    [message] => count(): Parameter must be an array or an object that implements Countable
    [file] => /core/runway/apps/perch_s3/lib/guzzlehttp/guzzle/src/Handler/CurlFactory.php
    [line] => 67
)

PHP Warning: count(): Parameter must be an array or an object that implements Countable in /core/runway/apps/perch_s3/lib/guzzlehttp/guzzle/src/Handler/CurlFactory.php on line 67

Perch Runway: 3.1.2, PHP: 7.2.7, MySQL: mysqlnd 5.0.12-dev - 20150407 - $Id: 38fea24f2847fa7519001be390c98ae0acafe387 $, with PDO
Server OS: Darwin, apache2handler
Installed apps: content (3.1.2), assets (3.1.2), categories (3.1.2), perch_blog (5.6.1), perch_forms (1.12), pipit_sharing (1.2.0)
App runtimes: <?php $apps_list = [ 'perch_blog', 'perch_forms', 'pipit_sharing', ];
PERCH_LOGINPATH: /lechateau
PERCH_PATH: /Users/Grant/Butterware/Lechateau/public/lechateau
PERCH_CORE: /Users/Grant/Butterware/Lechateau/public/lechateau/core
PERCH_RESFILEPATH: /Users/Grant/Butterware/Lechateau/public/lechateau/resources
Image manipulation: GD
PHP limits: Max upload 32M, Max POST 8M, Memory: 128M, Total max file upload: 8M
F1: 3b606135b33e6a102526838f4152a807
Resource folder writeable: Yes
HTTP_HOST: butterware.local
DOCUMENT_ROOT: /Users/Grant/Butterware/Lechateau/public
REQUEST_URI: /lechateau/core/settings/diagnostics/
SCRIPT_NAME: /lechateau/core/settings/diagnostics/index.php

Many thanks in advance for any help offered