connect prior to

I am trying to make a query on Projects that shows commitments on the lowest task level and all tasks above. I am close but the results are wrong. On the middle task level wrong tasks pop up.

This query shows the right 3 tasks:

select wbs_level, task_id, task_number, parent_task_id
from pa_tasks
where project_id = 1891
start with task_id = 256202 connect by prior parent_task_id = task_id
;

This query shows 4 tasks:

select t.task_id, t.parent_task_id,  a.line_type, t.task_number, sum(distinct ACCT_RAW_COST)
from pa_commitment_txns_v a, pa_tasks t