When scheduled daily job to synchronize the inventory versions fails to acquire lock, due to other parallel operations currently running, a task failure would be observed in the VMware Cloud Foundation task panel.
VCF 5.2
Synchronize inventory versions workflow failed to acquire lock. The Task "Acquire Lock" would fail, with error message saying "Lock is unavailable" and remediation to try again later. This can happen when another parallel workflow has already obtained the inventory lock, when the scheduled daily job triggers.
Manually restart the failed task in the task panel after the other parallel operations complete.
Alternatively, wait for the daily version synchronization to synchronize the inventory versions on the next scheduled run.