Hi Rajat,
unfortunately,our environment is still not reliable.
We have similar issues then do not take itas a reference.
However it was not possible retrieve data through the EPMRetrieveData because the measures for the periods not in hierarchy were not created.
How many EPM formula do you have in your sheet?
Have you tried to copy the same value in a different period (e.g. 2014.OCT) and check if the issue is still there?
Could you please share your time dimension?
Regards
Andrea