use Multi-Domains Plugin with WP Multi Network Plugin

Dear Team,
i run a WP multisite (v4.7) with WP Multi Network Plugin (v2.1) installed and activated.
i added several networks and tried to also enable the wpmudev Multi-Domains for Multisite Plugin (v1.3.4.5) on some of the networks to be able to use more than one domain for the selected networks.

everything works fine if i create new sites via backend, the new sites are created within the correct network.
but if a user registers or creates a new site on the frontend and uses the multi domain option the new site always gets created on the first network of the installation (site id1) instead of the network where the multi domain plugin is activated.

could you please help to solve this issue, i tried everything and wanted to use my wpmu subscription on this new project i am working on. is there a workaround or a patch available, or any other idea which might help?

thanks a lot,
eric