Nextcloud Server is a Nextcloud package that handles data storage. In versions priot to 19.0.13, 20.0.11, and 21.0.3, Nextcloud Server audit logging functionality wasn't properly logging events for the unsetting of a share expiration date. This event is supposed to be logged. This issue is patched in versions 19.0.13, 20.0.11, and 21.0.3.
https://security.gentoo.org/glsa/202208-17
https://hackerone.com/reports/1200810
https://github.com/nextcloud/server/pull/27024
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-fxpq-wq7c-vppf