Deep filtering WHERE OR issue

If i nest a _where with _where[_or] like this /articles?_where[0][_where[0][_or][guided_series_slug]]]=anxiety&_where[0][_where[0][_or][guided_series.slug]]]=depression&_where[0][_where[0][_or][guided_series_null]]=true

It looks to build the filtering object correctly

  start: 0,
  limit: 100,
  where: [ { field: null, operator: 'or', value: [
    { field: 'guided_series.slug', operator: 'eq', value: ['anxiety', 'depression'] },
    { field: 'guided_series', operator: 'null', value: 'true' }
] } ]

but it doesnt do an OR for the { field: 'guided_series', operator: 'null', value: 'true' } it does an AND instead

verified in the sql output

  sql: 'select distinct * from `articles` left join `strapi_cms`.`articles__guided_series` as `articles__guided_series_1` on `articles__guided_series_1`.`article_id` = `articles`.`id` left join `strapi_cms`.`guided_series` as `guided_series_1` on `articles__guided_series_1`.`guided-sery_id` = `guided_series_1`.`id` where (((((`guided_series_1`.`slug` = ?) or (`guided_series_1`.`slug` = ?))) and (`guided_series_1`.`id` is null))) limit ?',
  bindings: [ 'anxiety', 'depression', 100 ]

Any idea why? or any other ideas how to match items with particular relation values or has no relation

My bad, this works