Error
After upgrading from 1.3 to 1.5.3 my fullOuterJoinRelation started to give an error of "e { error: syntax error at or near "outer"

The SQL Output using .toSql()
I decided to output the sql for both 1.3 and 1.5.3 and below are the differences in syntax output
V1.3 - full outer join "item" as "child" on "child"."_parentId" = "item"."id" where "item"."_parentId"
V1.5.3 - outer join "children" as"child" where "item"."_parentId"

It seems that the 1.5.3 broke the fullOuterJoinRelation function as its not actually joining and is missing the "full" keyword which is required (outer keyword is optional)