SFTP Rename behavior

Hi, I'm having two different weird behaviors using the rename method on the SFTPClient class.

### Scenario 1
Here's an existing file structure
```
folder1/
folder1/file1.csv

folder1/subfolder1/
folder1/subfolder1/file1.csv
```

Given this structure, the command I send is:
```
sftpClient.rename("folder1/file1.csv", "folder1/subfolder1/file1_1.csv");
```

The resulting structure is:
```
folder1/

folder1/subfolder1/
folder1/subfolder1/file1_1.csv
```

The file1.csv within subfolder1 was either deleted or renamed. This shouldn't happen. I expect this folder structure afterwards:
```
folder1/

folder1/subfolder1/
folder1/subfolder1/file1.csv
folder1/subfolder1/file1_1.csv
```

### Scenario 2
Sometimes when I rename the file, it appends its own random number to the end, which lives temporarily(sometimes) before going to its final name.

File Structure
```
folder1/
folder1/file1.csv

folder1/subfolder1/
```

Given this structure, the command I send is:
```
sftpClient.rename("folder1/file1.csv", "folder1/subfolder1/file1.csv");
```

The resulting structure is:
```
folder1/

folder1/subfolder1/
folder1/subfolder1/file1_382192394.csv
```

If I keep hitting refresh on Filezilla the name will SOMETIMES, but not always end up reverting back to file1.csv giving me the desired file structure of:
```
folder1/

folder1/subfolder1/
folder1/subfolder1/file1.csv
```

I'm not entirely sure where the problem is in these situations, whether with SSHJ or with the SFTP Server we're using. Here is some information on what I'm working with.

```
$ java -version

java version "1.8.0_73"
Java(TM) SE Runtime Environment (build 1.8.0_73-b02)
Java HotSpot(TM) 64-Bit Server VM (build 25.73-b02, mixed mode)
```

We're using sshj v0.19.0
SFTP server info:
`Windows_NT version 5.0 (MOVEit DMZ FTP 8.3.0.0)`
it claims to be communicating using SFTPv3

Thanks in advance!