Sonarr unable to import files

Sonarr version (exact version): 3.0.3.644
Mono version (if Sonarr is not running on Windows): Mono JIT compiler version 6.4.0.198
OS: Ubuntu Ubuntu 16.04.6 LTS
Debug logs: https://pastebin.com/0rgwff7d
Description of issue:

The 27 september Sonarr suddenly stopped importing downloaded content.

Sonarr tries to say it does not have access, this is however not true, nothing was changede, and system says other wise

Download destination - permissions
drwxrwxr-x 2 otheruser sonarr 0 Oct 2 20:42 Temp/

Move destination
drwxrwxr-x 2 otheruser sonarr 0 Sep 27 22:57 serier/

Sonarr is run as Sonarr
top | grep sonarr
6044 sonarr 20 0 1588872 204748 31384 S 12.5 4.2 1:10.13 mono

I’ve been having the same issue since the last patch, but am only running Sonarr 2.

Sonarr version (exact version) : 2.0.0.5338
Mono version (if Sonarr is not running on Windows) : Mono JIT compiler version 6.0.0.334
OS : CentOS Linux 7

When trying to copy files to my server (A synology 918+), Sonarr starts copying the file just fine (with the .partial appearing on the server). However, once the file is fully copied, and Sonarr attempts to rename it, an error appears in the log saying that it does not have access.

Sonarr then proceeds to try to copy a different file, and the same error occurs. This is particularly annoying, because it causes continuous network traffic and hard drive writing.

I am pretty confident all of the permissions are set correctly.