Hello Vimal,
This behavior might be due to the caching mechanism used by Microsoft Graph API, which could result in some delay before changes are reflected. Possibly, one of the user's requests was served from a cached response (resulting in stale label), while the other user got it from the data source (resulting in latest label).
I see you have already waited for 48 hours but at times, if your tenant spans multiple regions or availability zones, replication delays can sometimes lead to inconsistency in API responses.
Hope that clarifies. If this is not a one-off occurrence and seems to happen consistently with predictable delay, I would suggest getting in touch with Microsoft Support.
If you found the information above helpful, please Accept the answer. This will assist others in the community who encounter a similar issue, enabling them to quickly find the solution and benefit from the guidance provided.