CIFS VFS: Closed unmatched open between TrueNAS and Ubuntu client

[inittab]

Hello,
I am having issues with an Ubuntu 20.04.2 LTS VM and a CIFS mount on my TrueNAS server. Occasionally I will get the following Error in dmesg on the ubuntu client:

Code:

[Thu Jun 17 11:53:38 2021] CIFS VFS: Close unmatched open
[Thu Jun 17 11:53:47 2021] CIFS VFS: Close unmatched open
[Thu Jun 17 11:53:47 2021] CIFS VFS: Close unmatched open
[Thu Jun 17 11:53:53 2021] CIFS VFS: Close unmatched open

These message correspond to an error message in the client software accessing the share:

Code:

[v3.0.6.1196] System.IO.IOException: Interrupted system call
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].FindNextEntry (System.Byte* entryBufferPtr, System.Int32 bufferLength) [0x0004c] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].FindNextEntry () [0x0001d] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].DirectoryFinished () [0x00033] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].FindNextEntry (System.Byte* entryBufferPtr, System.Int32 bufferLength) [0x0001d] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Enumeration.FileSystemEnumerator`1[TResult].MoveNext () [0x00054] in <533173d24dae460899d2b10975534bb0>:0
  at System.Collections.Generic.LargeArrayBuilder`1[T].AddRange (System.Collections.Generic.IEnumerable`1[T] items) [0x0003d] in <533173d24dae460899d2b10975534bb0>:0
  at System.Collections.Generic.EnumerableHelpers.ToArray[T] (System.Collections.Generic.IEnumerable`1[T] source) [0x00033] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.MonoLinqHelper.ToArray[T] (System.Collections.Generic.IEnumerable`1[T] source) [0x00000] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Directory.GetFiles (System.String path, System.String searchPattern, System.IO.EnumerationOptions enumerationOptions) [0x00009] in <533173d24dae460899d2b10975534bb0>:0
  at System.IO.Directory.GetFiles (System.String path, System.String searchPattern, System.IO.SearchOption searchOption) [0x00008] in <533173d24dae460899d2b10975534bb0>:0
  at NzbDrone.Common.Disk.DiskProviderBase.GetFiles (System.String path, System.IO.SearchOption searchOption) [0x00047] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskProviderBase.cs:164
  at NzbDrone.Core.MediaFiles.DiskScanService.GetNonVideoFiles (System.String path, System.Boolean allDirectories) [0x00019] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\DiskScanService.cs:170
  at NzbDrone.Core.Extras.ExistingExtraFileService.Handle (NzbDrone.Core.MediaFiles.Events.SeriesScannedEvent message) [0x0004c] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Extras\ExistingExtraFileService.cs:43
  at NzbDrone.Core.Messaging.Events.EventAggregator.PublishEvent[TEvent] (TEvent event) [0x0011a] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\Messaging\Events\EventAggregator.cs:92


root@gluttony[/mnt/datatank/media]# grep -B 2 "Interrupted system call" sonarr.txt | grep 11:53
21-6-17 11:53:38.9|Error|RefreshSeriesService|Couldn't rescan series [110381][Archer (2009)]
21-6-17 11:53:47.4|Error|RefreshSeriesService|Couldn't rescan series [293996][The Asterisk War: The Academy City on the Water]
21-6-17 11:53:47.7|Error|RefreshSeriesService|Couldn't rescan series [106301][Atom Ant]
21-6-17 11:53:53.6|Error|EventAggregator|ExistingExtraFileService failed while processing [SeriesScannedEvent]
root@gluttony[/mnt/datatank/media]#

TrueNAS information is in sig, but it's fully updated, ubuntu vm is also fully updated

cifs mounted with:

Code:

/etc/fstab:
//10.0.103.4/media      /mnt/media      cifs    dir_mode=0775,file_mode=0775,uid=downloads,gid=downloads,credentials=/etc/smb.cred      0 0
mount | grep media:
//10.0.103.4/media on /mnt/media type cifs (rw,relatime,vers=3.1.1,cache=strict,username=downloads,uid=1005,forceuid,gid=1005,forcegid,addr=10.0.103.4,file_mode=0775,dir_mode=0775,soft,nounix,serverino,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=60,actimeo=1)

I have tried older cifs versions but this doesn't really seem to have an effect on the error message received.
I also have a packet capture from the above time period from the TrueNAS server but would rather not post it publicly but can make it available privately.

Any help on this issue would be appreciated, This issue seems to happen randomly and isn't directly related to a specific directory, or set of files.
Debug Log is also attached.
Thanks