I believe Coremelt's plugins are licensed for 1 machine. If you also have the plugin on another Mac, that may be what is triggering the "Trial" watermark. If not, I suggest you send Coremelt a support ticket from their website. They are a reliable developer and respond quickly.
Got the same issue. I can't even open the Registration window to license the plugins. Are they even working properly under m1? I kept getting a window saying "Lost contact with Helper Application" or something like that.
Have you downloaded and installed the latest updates? Just download from their downloads page, even if it says demo, it'll find the license in your system and work fine. But be sure you have the latest versions. Then contact their tech support directly. They're pretty good taking care of customers.