Hi Juan,
we ran into the same error.
You can add follwing to the discovery.cfg (config/modules/discovery.cfg):
discovery.index.authority.ignore-prefered=true
discovery.index.authority.ignore-variants=true
discovery.browse.authority.ignore-prefered=true
discovery.browse.authority.ignore-variants=true
Part of information about this configs can you read here:
But the "discovery.browse.authority" key isn't documented (anymore?), but neccessary to build search index successfully - without authority information!
Best regards
Manuele