Reportedly Calendar entries have disappeared from Windows Phone with missing Sync Option

It seems many Windows Phone users are reporting that Calendar entries have gone missing and the calendar just looks blank even when it is enabled under the calendar settings.  Not only this but many users ( Including Me ) are also reporting that the Sync Option under primary Microsoft or live account configured is also not there but is available for any other Live Account which is configured on the same phone.

Like you can see in the screenshots below that one of my Live Id has option to sync Email, Calendar, Task, Contacts do but for main live account, I just have Email Sync available. Even though all the calendar is available online or the desktop version. There are also many threads in the Microsoft Forums complaining about the same.

One thing I noticed is that when I make a new entry, it appears in the desktop version. So it’s probably some temporary issue that calendar sync is facing and it has turned off all syncing option in the phone as this option is not available for mobile devices.

Are you facing the issue ?

Thanks Kamaljeet