Can you please revert the issue title to the original "where clause for non owned one-to-one relation generates incorrect SQL" or something similar. The current title is missleading in my opinion, because I don't think it is an implicit join, nor do I think it should generate a left join and this is specific for the non-owned side of a one-to-one relation.
I think the current title makes it harder to find and understand this issue for people that have the same problem as me and search for this.