Ok… let’s see. I’m also using sonarr in the linuxserver docker on synology, so our setups are virtually the same…
When you add a series, this is what the path dropdown should look like:
If you have multiple paths there (e.g. /tv/Colony, /tv/otherseries…) that’s incorrect.
To fix: remove the series that are in there from sonarr, then click the “add a different path” option in the dropdown above. From the Select Folder dialog, you can use the red x to delete everything and only keep /tv/.
Then you can add the series again and just select /tv/ as the path. That should do it, I think.