Hi Ritesh,
Is Calendar Year/Month the standard 0CALMONTH for both queries? If not check data types match exactly at the bw layer.
Is Calendar Year/Month the only dimension in the table? The second column's header is also showing #SYNTAX... weird !.
If you used the merged dimension in the table's first column, have you tried using Query 1's or Query 2's dimension instead (without unmerging)? Or viceversa if you're not using the merged dimension... You can try changing the dimension and see if things work different.
Difficult to give a valuable advice... looks like there's a problem with that version. This might be an obvious or a silly advice, but before reporting a bug to sap or looking somewhere else... have you tried recreating your bics connections and the report?
Check all the parameters of your olap bics connection are OK. I had a similar experience one occasion I accidentally mixed dev and prd parameters by mistake in a prd connection. The connection was working but the report had erratic behaviour like #SYNTAX or #UNAVAILABLE.
Regards,
Fernando