Hello!
It seems that you use fragment with CUBA schema in screen with Jmix schema. In this case, the screen uses Jmix ComponentLoaderContext and CUBA components from the fragment can fail to load.
You can try to migrate your fragment to the Jmix schema:
<fragment xmlns="http://jmix.io/schema/ui/fragment">
...
</fragment>
With this schema fragment will load Jmix instances of components.