Weird, looks like during shim-signed installation, when the bcmwl dkms module is uninstalled to be signed, a check for the dkms status fails expectations. For some reasons shim-signed expects the uninstalled module to return status 'built' (which it does on my cosmic system here), but on disco this seems to result in something else. It feels to me that the behavior of dkms changed between cosmic and disco and now either dkms uninstall removes the module completely (not resulting in being 'built' after the uninstall) or maybe dkms reports the status wrongly (differently).
Weird, looks like during shim-signed installation, when the bcmwl dkms module is uninstalled to be signed, a check for the dkms status fails expectations. For some reasons shim-signed expects the uninstalled module to return status 'built' (which it does on my cosmic system here), but on disco this seems to result in something else. It feels to me that the behavior of dkms changed between cosmic and disco and now either dkms uninstall removes the module completely (not resulting in being 'built' after the uninstall) or maybe dkms reports the status wrongly (differently).