BDocs stay yellow - status I02 Written to qRFC Queue (intermediate state)

Question

We upgraded our system from SAP CRM 7.0 EHP3 SP3 to SP4.
Now all the BDocs in smw01 stay yellow. I can manually reprocess them, then they become green. There is no error message and there are no dumps in st22.
The CSA* queues are registered. The scheduler says "inactive" (and briefly goes to active when saving a business partner, product or transaction, as it should).
The CSA* queues relevant for each "stuck" business partner, transaction or product is in status "STOP".
There's a note, 1593693 - BDoc's in state I02, but it doesn't help. We don't have a problem with the number or load of the RFC processes (as far as I can tell), there is very little going on on the system, right now I am the only one logged on) and the queues are not in status READY, either.
MW_CHECK says "All post-processing steps are done."
GENSTATUS counts 0 errors or waiting.
MW_MODE is on, of course.
smw3_00 is empty (which it was before the SP installation, too).
The CRM is not connected to an ERP system, it sends búsiness partner and transactional data via the XIF adapter (via web services). Which, up to now, worked just fine.

Answer 1

I was given the solution: Use transaction smq2, search for CSA*, click on the queue, click the unlock button. That worked.