Problem with session_path

[awcip]

Thanks for a very interesting project. I am however having trouble understanding the session_path configuration for containers.
Using a transmission docker container from e.g. linuxserver the session_path should be /config/ since the torrents are stored in /config/torrents. I thought that I could run two transmission instances and the spreadsheetui in a docker on the same host and mount the /config directory from each transmission instance into the spreadsheet container and set the session_path for each instance according to how I mounted it, but it does not seem to find the file:

[stderr#error]   File "/usr/local/lib/python3.7/site-packages/libtc/clients/transmission.py", line 213, in retrieve_torrentfile
[stderr#error]     raise FailedToExecuteException("Torrent file does not exist")
[stderr#error] libtc.exceptions.FailedToExecuteException: Torrent file does not exist

What is it I am not understanding? I have attached my simplified configs, which I think should be enough.

My docker-compose.yml:

transmission-one:
volumes:
   - ./transmission/one:/config
...
transmission-two:
volumes:
   - ./transmission/two:/config
...
spreadsheetui:
volumes:
  - ./transmission/:/transmission

spreadsheetui config.toml:

[clients.transmission-one]
display_name = "transmission-one"
client_type = "transmission"
url = "http://user:pass@transmission-one:9091/transmission/rpc"
session_path = "/transmission/one"

[clients.transmission-two]
display_name = "transmission-two"
client_type = "transmission"
url = "http://user:pass@transmission-two:9091/transmission/rpc"
session_path = "/transmission/two"