@alexdi I can confirm that we have the same issue. We are able to connect OpenStack Swift in Compatibility mode, however we are not able to use it as Distributed Cached Store for Reflexions, or even reading parquet files hosted in the object storage.
We have already provided a solution to Dremio Team since Dec 2020, but the issue still persists.
We have also tested this issue with version15.0, sitll same results:
S3Exception: The authorization header is malformed; the region ‘us-east-1’ is wrong; expecting ‘BHS’ (Service: S3, Status Code: 400, Request ID: txd785d13046bd40eca97ca-006072f251)