clap plugins fail to load

hi, i'm excited about clap, the new plugin format :) tried installing podolski by u-he. downloaded the tar.xz and run the installer script. the vst and vst3 versions work. but the clap version fails to scan. i have also compiled the minimal example plugin by schwaaa. that wasn't very fun, but i managed somehow. this one also fails when reaper scans the plugins folder. i see no errors from the terminal. running xubuntu 20.04 pulseaudio and reaper 6.71 native. from what i understand, hosts can choose what clap extensions to support, and they must match the ones used by the plugin to work. maybe there's a mismatch here? thanks

There is a page with all CLAP plugins here:

Various plug-ins I created here (they're very nice :) ) VST2, VST3, CLAP and JACK versions included (500X-Series plug-ins and SA Series). Demos are free to download, plug-ins come with their own installer, comprehensive manual and plug-in validation documentation.