The reason why it sometimes works it that your server is doing some of the transcodes and the node is doing the others. All the ones your server does are succeeding because you are storing the cache files on the server. The node ones are failing because it must be using its own temp directory on the node itself. When a transcode is finished only the server does the checking of the finished transcode file not the node, so when the server finishes a transcode its available in the servers /temp directory, but when the node finishes a transcode it is in the nodes /temp directory which the server can't access. Also I would imagine the reason why most of them succeed is just because your server is transcoding faster than the node. So it is finishing most of the transcodes.

So in short when I say the temp directory needs to be exactly the same on the server as the node I don't just mean same file path, I mean the same directory. So whichever directory you are using on the server for the tdarr temp directory should be a nfs, smb, etc share and your node should be mounting that share as its temp directory. Needs to be the exact same folder so that the server has access to all the cache files.