Hey Ondrej,
This ticket must fallen through the cracks post GDC week - thank you for pinging me on this and your patience! One thing I will note here is that our 5.6 release will be around the corner, and there have indeed been further improvements and bugfixes to Storage.
I am curious whether the job that is responsible for producing the blobs is failing to upload them? Do you have any of the agent logs associated with the producer?
Kind regards,
Julian