import crashes with SimpleXMLElement::addAttribute() expects parameter 2 to be string, object given

[peerlight]

Bug description

import crashes with SimpleXMLElement::addAttribute() expects parameter 2 to be string, object given

Steps to reproduce

hit button "Import ausführen" in Contao or let cron work

Expected behavior

import of data in files/maklermodul/upload

Log

Contao says SimpleXMLElement::addAttribute() expects parameter 2 to be string, object given
Log writes

[2022-09-29 14:20:17] request.INFO: Matched route "contao_backend". {"route":"contao_backend","route_parameters":{"_route":"contao_backend","_scope":"backend","_token_check":true,"_controller":"Contao\\CoreBundle\\Controller\\BackendController::mainAction"},"request_uri":"https://www.DOMAIN.de/contao?act=import&do=maklermodulSetup&ref=p9tdd8Nq","method":"GET"} []
[2022-09-29 14:20:17] request.CRITICAL: Uncaught PHP Exception TypeError: "SimpleXMLElement::addAttribute() expects parameter 2 to be string, object given" at /www/htdocs/.../vendor/pdir/maklermodul-sync-bundle/src/Classes/Domain/Model/ImportTarget.php line 511 {"exception":"[object] (TypeError(code: 0): SimpleXMLElement::addAttribute() expects parameter 2 to be string, object given at /www/htdocs/.../vendor/pdir/maklermodul-sync-bundle/src/Classes/Domain/Model/ImportTarget.php:511)"} []

Environment

PHP 7.4.30
Contao 4.9.34
maklermodul-bundle 2.8.1
maklermodul-sync-bundle 2.7.1

[MDevster]

Fixed in 2.8.2