Hi everyone,

I'm experiencing a sync behavior where files work on some devices but not others, and the problem reverses depending on how the file was added.
My Setup

Desktop app: Windows
Mobile device: Boox tablet
Web library: Can see all files

The Problem
Depending on how I added a file, it does not work on either the app or my Boox.
app boox web library

uploaded (PDF) in zotero -dekstop library No Yes Yes

added via browser extension Yes No Yes

All files appear in the web library, but each has access issues on specific devices. There is no lync between Boox and app - files can be seen, but only files that can not be opened in the app can be opened in Boox and vice versa. When PDFs are directly added to Web library there is no possibility for me to add any information

Additional Observations

When trying to open files on the web library, I see console errors including repeated 404 responses for tagColors API endpoints and missing SVG icons
Console errors shown below:

api.zotero.org/users/[redacted]/settings/tagColors?format=json:1 Failed to load resource: the server responded with a status of 404 ()
/static/web-library/icons/12/item-type/link.svg#link-white:1 Failed to load resource: the server responded with a status of 404 ()

What I've Tried

Checking sync status on all devices
Verifying files are visible in web library
Pull-down sync on Boox

Questions

Should I be seeing 404 errors on tagColors API calls? Is this a known issue?
Is there a setting that controls which device receives the actual file vs. just metadata?
What diagnostic steps would help narrow this down?

Any insights or next steps for debugging would be appreciated! I really need to be able to access these files from all my devices and for them to sync.

All the best,
R.B.