Folder sharing not updating on specific sharing clients


I have a nextcloud 12 server setup with a folder I share with 2 collegues.

The 1st collegue is set to full access (read and write)
The 2nd collegue is set to only read access

When I make changes to the shared folder (say adding a file) it is only updated on the nextcloud instance for the 2nd colleague with only read access. It appears that the 1st colleague who has both read and write access do not have the shared folder updated. This appears to happen on server level as when I log into nextcloud online dashboard with the 1st colleague credentials their folder structure is different than that of mine. It appeared to have worked fine until the 15th of this month as there has not been any new changes for them since then. I have also ran sync multiple times on the colleagues computer but no luck.

We have a 2nd folder also shared amongst eachother which appears to work exactly as it should so not sure what could be the cause of this?

Any ideas?