Jetpack Sync Module ArgumentCountError

A recent update to Jetpack appears to be causing issues with WP Cassify. We are noticing a WSOD after logging in to wp-admin. Reloading wp-admin bypasses the WSOD.

The error 500 is recorded as an ArgumentCountError with Jetpack_Sync_Module_Users. The full error and stack trace are below.

Network deactivating Jetpack makes the error go away. Re-activating Jetpack makes the error come back.

We are running Jetpack 7.2.1 and WordPress 5.1.1 and WP Cassify 2.1.8.

Error message
ArgumentCountError: Uncaught exception ‘ArgumentCountError’ with message ‘Too few arguments to function Jetpack_Sync_Module_Users::wp_login_handler(), 1 passed in wp-includes/class-wp-hook.php on line 286 and exactly 2 expected’ in wp-content/plugins/jetpack/sync/class.jetpack-sync-module-users.php:175

Stack trace
in Jetpack_Sync_Module_Users::wp_login_handler called at //wp-includes/class-wp-hook.php (286)
in WP_Hook::apply_filters called at /wp-includes/class-wp-hook.php (310)
in WP_Hook::do_action called at /wp-includes/plugin.php (465)
in do_action called at /wp-content/plugins/wp-cassify/classes/wp_cassify_utils.php (244)
in wp_cassify\WP_Cassify_Utils::wp_cassify_auth_user_wordpress called at /wp-content/plugins/wp-cassify/classes/wp_cassify_plugin.php (483)
in wp_cassify\WP_Cassify_Plugin::wp_cassify_grab_service_ticket called at /wp-includes/class-wp-hook.php (286)
in WP_Hook::apply_filters called at /wp-includes/class-wp-hook.php (310)
in WP_Hook::do_action called at /wp-includes/plugin.php (465)
in do_action called at /wp-settings.php (505)
in require_once called at /wp-config.php (268)
in require_once called at /wp-load.php (37)
in require_once called at /wp-admin/admin.php (34)
in require_once called at /wp-admin/index.php (10)