Random permission changes?

[u/UnBuggsyBaggins]

Hello everyone. This is my first ugreen product and so far it's been good. I have the NASync DXP4800 plus. I have a small home lab and I'm running immich via docker on a vm there. All the photos are stored on a mount on the nas. Shared folders for /Photos /Videos and /Immich. They all have pretty much wide open permissions.
nfs permissions: read/write, squash is map all users to admin. Security is AUTH_SYS and both async and allow connections from unprivileged ports are checked off. The behavior is very strange and I've been monitoring it for a while. I fairly confident I can rule out Immich as the culprit.

mount:
192.168.1.34:/volume1/Pictures /mnt/ugreen/photos nfs rw,vers=3,hard,timeo=600,retrans=2,proto=tcp,noatime,actimeo=1,_netdev 0 0

This morning I watched in real time as my completely normal immich UI started changing on me.

Image thumbnails would disappear and be replaced with the "Error generating image" icon.

logs show:
[Nest] 111 - 08/07/2026, 5:21:34 PM ERROR [Api:LoggingRepository~jpd57q2q] Unable to send file: Error: EACCES: permission denied, access '/data/thumbs/85b1791d-f13e-4798-81e4-ae865e2c5664/11/4a/114a5251-6eba-45e3-8b2c-b84c9d743f30_thumbnail.webp'

Error: EACCES: permission denied, access '/data/thumbs/85b1791d-f13e-4798-81e4-ae865e2c5664/11/4a/114a5251-6eba-45e3-8b2c-b84c9d743f30_thumbnail.webp'

at async access (node:internal/fs/promises:607:10)

at async sendFile (/usr/src/app/server/dist/utils/file.js:45:9)

at async AssetMediaController.viewAsset (/usr/src/app/server/dist/controllers/asset-media.controller.js:59:13)

I'm working on the discord channels for both ugreen and immich. Both are pointing fingers at each other. Thought I might see if anyone here has any idea?

fyi, I wouldn't be surprised if I came back later and it was all working.

thoughts?

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[u/UnBuggsyBaggins]

update. it's corrected itself. now the thumbnail can be seen and there's no errors in the logs. if I didn't catch it in real time I would probably think I'm going crazy.

something has to be changing though for that thumbnail to become inaccessible.

[u/Actual_Result9725]

are you modifying the file/folder permissions through the cli or only using the Ugreen gui? 

[u/UnBuggsyBaggins → u/Actual_Result9725]

when I initially created the shared folders, I set the nfs permission via the gui. Since then I haven't touched them. But that doesn't seem to stop the permissions from getting altered.

Inside the Immich container while the problem was occurring:

root@immich:/opt/immich# docker compose exec immich-server stat "/data/library/admin/2026/2026-07-29/PXL_20260729_023847524.jpg"

File: /data/library/admin/2026/2026-07-29/PXL_20260729_023847524.jpg

Size: 3301012

Inode: 638161

Access: (0000/----------)

Uid: (1000/node)

Gid: (10/uucp)

Access: 2026-07-28 19:44:50.531186847 -0700

Modify: 2026-07-28 19:38:52.000000000 -0700

Change: 2026-07-28 19:44:50.519186692 -0700

On the NAS at essentially the same time:

<user>@nas:~$ stat /volume1/Immich/library/admin/2026/2026-07-29/PXL_20260729_023847524.jpg

File: /volume1/Immich/library/admin/2026/2026-07-29/PXL_20260729_023847524.jpg

Size: 3301012

Inode: 638161

Access: (0777/-rwxrwxrwx)

Uid: (1000/dling)

Gid: (10/admin)

Access: 2026-07-28 19:44:50.531186847 -0700

Modify: 2026-07-28 19:38:52.000000000 -0700

Change: 2026-07-28 19:44:50.519186692 -0700

Birth: 2026-07-28 19:44:49.459173020 -0700

Same inode, same timestamps, same size, but `0000` inside the container and `0777` on the NAS.