I opened a Ticket with Magix Support about DirectX Plugin Presets not appearing when the plugins are opened again. The response they sent was this:
"Unfortunately, the recall of the plugin's previous properties repeatedly led to crashes in versions 16 and 17. Since we want to ensure a high compatibility with many modern plugins, this recall is no longer available in version 18, which makes the software more stable".
I think Magix has no interest in solving the issue.