Hi Denise,
I see, this indeed sounds annoying.
Unfortunately I am running out of ideas what more things you can try:
- Clearing temporary BW-hierarchy tables once is definitely worth a try.
- Also checking if the query is behaving differently in case that cache/aggregates/BWA is deactivated might help on the root cause analysis. You can check so by excuting the query in transact RSRT2 and clicking on the right corner of "Execute&Debug" -> Execute in Save mode.
If all of this does not bring any further you may consider opening an SAP incident on componen BW-BEX-OT-OLAP-HIER.
BR Bernhard