Sonarr moves file after download but claims it didn't

Sonarr version (exact version): 4.0.9.2244
Mono version (if Sonarr is not running on Windows): 6.12.0.182-20
OS: Synology 7.1.1
Debug logs:
Description of issue:

Sonarr uses NZBGet to download a file on my Synology. NZBGet has a root folder on the system that downloads go into. At the completion of the download, Sonarr then moves the completed file into the correct directory (with season folders) and notifies Plex the new file is there. All of this works fine. Except, Sonarr reports in the queue that it was “Unable to import automatically” and it never deletes the original download. I now have two copies of the file and Sonarr thinks it never imported it.

Sonarr log (below) is reporting permissions issues on the Synology. I have given every user (system and local) read/write to the two shared folders where all this is going on. There should be no permission issues.

[v4.0.9.2244] System.UnauthorizedAccessException: Access to the path '/volume1/NZBGet/completed/TV/For.All.Mankind.S04E05.Goldilocks.720p.ATVP.WEB-DL.DDP5.1.H.264-NTb/abbc375c6e384d17b6b6ac12e446d802.mkv' is denied.
 ---> System.IO.IOException: Permission denied
   --- End of inner exception stack trace ---
   at System.IO.FileSystem.DeleteFile(String fullPath)
   at NzbDrone.Common.Disk.DiskTransferService.TransferFile(String sourcePath, String targetPath, TransferMode mode, Boolean overwrite) in ./Sonarr.Common/Disk/DiskTransferService.cs:line 296
   at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.TransferFile(EpisodeFile episodeFile, Series series, List`1 episodes, String destinationFilePath, TransferMode mode, LocalEpisode localEpisode) in ./Sonarr.Core/MediaFiles/EpisodeFileMovingService.cs:line 170
   at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.MoveEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode) in ./Sonarr.Core/MediaFiles/EpisodeFileMovingService.cs:line 81
   at NzbDrone.Core.MediaFiles.UpgradeMediaFileService.UpgradeEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode, Boolean copyOnly) in ./Sonarr.Core/MediaFiles/UpgradeMediaFileService.cs:line 80
   at NzbDrone.Core.MediaFiles.EpisodeImport.ImportApprovedEpisodes.Import(List`1 decisions, Boolean newDownload, DownloadClientItem downloadClientItem, ImportMode importMode) in ./Sonarr.Core/MediaFiles/EpisodeImport/ImportApprovedEpisodes.cs:line 158

2024-09-18 09:13:28.5|Warn|ImportApprovedEpisodes|Couldn't import episode /volume1/NZBGet/completed/TV/For.All.Mankind.S04E05.Goldilocks.720p.ATVP.WEB-DL.DDP5.1.H.264-NTb/abbc375c6e384d17b6b6ac12e446d802.mkv

[v4.0.9.2244] NzbDrone.Common.Disk.DestinationAlreadyExistsException: Destination /volume1/Plex/TV Shows/For All Mankind (2019)/Season 4/For All Mankind - S04E05 - Goldilocks WEBDL-720p.mkv already exists.
   at NzbDrone.Common.Disk.DiskTransferService.ClearTargetPath(String sourcePath, String targetPath, Boolean overwrite) in ./Sonarr.Common/Disk/DiskTransferService.cs:line 403
   at NzbDrone.Common.Disk.DiskTransferService.TransferFile(String sourcePath, String targetPath, TransferMode mode, Boolean overwrite) in ./Sonarr.Common/Disk/DiskTransferService.cs:line 296
   at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.TransferFile(EpisodeFile episodeFile, Series series, List`1 episodes, String destinationFilePath, TransferMode mode, LocalEpisode localEpisode) in ./Sonarr.Core/MediaFiles/EpisodeFileMovingService.cs:line 170
   at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.MoveEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode) in ./Sonarr.Core/MediaFiles/EpisodeFileMovingService.cs:line 81
   at NzbDrone.Core.MediaFiles.UpgradeMediaFileService.UpgradeEpisodeFile(EpisodeFile episodeFile, LocalEpisode localEpisode, Boolean copyOnly) in ./Sonarr.Core/MediaFiles/UpgradeMediaFileService.cs:line 80
   at NzbDrone.Core.MediaFiles.EpisodeImport.ImportApprovedEpisodes.Import(List`1 decisions, Boolean newDownload, DownloadClientItem downloadClientItem, ImportMode importMode) in ./Sonarr.Core/MediaFiles/EpisodeImport/ImportApprovedEpisodes.cs:line 158

2024-09-18 09:13:29.1|Info|DiskScanService|Scanning For All Mankind
2024-09-18 09:13:30.4|Info|DiskScanService|Completed scanning disk for For All Mankind
2024-09-18 09:13:30.5|Info|ExistingMetadataImporter|Found 0 existing metadata files
2024-09-18 09:13:30.5|Info|ExistingSubtitleImporter|Found 0 existing subtitle files
2024-09-18 09:13:30.5|Info|ExistingOtherExtraImporter|Found 0 existing other extra files
2024-09-18 09:13:30.5|Info|ExistingExtraFileService|Found 0 possible extra files, imported 0 files.

Per the snippet, seems to be permissions related: see Trash for recommended setup, including permissions fix

https://trash-guides.info/Hardlinks/How-to-setup-for/Synology/