Hello Julian ..
I switched today to the new uibuilder.esm.js .. all is good with my application that uses a build step.
One thing i noticed is that because i wasnt loading a css file (all css was in each .vue file)
the uib-brand.css file was loading but clashing with existing bootstrap-vue css styles.
So i tried to pass the loadStylesheet option setting it to false .. but that didnt make a difference.
As a workaround i loaded a fake css so the code responsible of loading uib-brand.css wouldnt kick in ?
// uibuilder.debug(true);
uibuilder.start({ ioNamespace: "/navbar", loadStylesheet: false });
Also uibuilder.debug(true); doesnt seem to enable debug msgs