If you could download and test one of those and confirm that it fixes the bug, that would be most helpful!
If it does not, please run rclone version to double-check you are testing the right version (and not some previous version installed on your system.) The version should match this exactly:
When you get an object without specifying a versionId in your request, if its current version is a delete marker, Amazon S3 responds with the following:
A 404 (Not Found) error
A response header, x-amz-delete-marker: true
When you get an object by specifying a versionId in your request, if the specified version is a delete marker, Amazon S3 responds with the following:
A 405 (Method Not Allowed) error
A response header, x-amz-delete-marker: true
A response header, Last-Modified: timestamp (only when using the HeadObject or GetObject API operations)
iDrive E2 API will return 405 even for HEAD request without: versionId specified which is clearly not in line with the above description and with what other S3 providers are doing.
Ideal solution would implement this workaround solely for iDrive E2, but proposed fix shouldn't really break anything, it's just less strict.