Are you on the latest OS3 firmware? Note I’m still using the older v4 firmware so I can’t really know what’s exactly has changed in the dir structures.
By right when you install transmission from this installer, it will place all the necessary paths in /shares/Public/Transmission. But if you change them, you’ll need to ensure the correct permission/ownership for the new paths yourself.
Try:
chmod -R 2777 /shares/Public/Transmission>/dev/null 2>&1; chown -R :share /shares/Public/Transmission>/dev/null 2>&1;
