Files received by the SFTP server component are not valid

Here is my scenario:

I declared a simple rule to just receive the file:

$ wg rule get recv receive● Rule recv (receive)
    Comment:        
    Path:           /path
    In directory:   
    Out directory:  
    Work directory: 
    Pre tasks:
    Post tasks:
    Error tasks:
    Authorized agents:
    ├─Servers:          
    ├─Partners:         
    ├─Server accounts:  
    └─Partner accounts: 

I upload a file using this rule:

$ ls -ls /vagrant/data_1m.dat 
1236 -rw-r--r--. 1 vagrant vagrant 1264430 Dec  7  2020 /vagrant/data_1m.dat
$ lftp sftp://sftpclient:password@127.0.0.1:6621/ -e "set ssl:verify-certificate false;  set sftp:auto-confirm true; put -O /path /vagrant/data_1m.dat -o test-receive.txt; bye"
cd: Access failed: failed to retrieve rule for path '/' 
1264430 bytes transferred                                          

The transfer has no errors:

$ wg transfer list
No transfers found.

But the content of the file is incorrect:

$ sudo diff /var/lib/waarp-gateway/in/test-receive.txt /vagrant/data_1m.dat
Binary files /var/lib/waarp-gateway/in/file_sftpclient-r66server.dat and /vagrant/data_1m.dat differ

By opening the received file, I observed that (splitting the file in 32768 byte blocks) :

• The first block just contains null bytes (\0)
• The first block of the original file has been written as the 7th block of the received file.