SSRS report not returning current data

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SQL

SSRS

m creating a report in SSRS. The report needs to be generated daily. when I run the query in SQL server, it gives me accurate data. However, when the report is generated it gives me data only for the last date of last month. I'm using this to call yesterday/today . I have tried using 1st date of august as start date and September end as end date using the same "getdate" format , and the report runs ok. I am using the same query as the dataset of my report. What am I missing.Thanks so much for your help!!

^^^I'm just baffled that even if I go in and put START DATE as 10/11/16 and END DATE as 10/12/2016 is returns the value of 09/30/2016. If SD is 09/01/16 anD END DATE is 10/12/16 the data for whole of September is returned.No data for October is returned.

DECLARE @PRD_GRP VARCHAR(3)
DECLARE @START_DATE DATETIME
DECLARE @END_DATE DATETIME
SET @PRD_GRP =  'RDE'
SET @START_DATE = DATEADD(d,-1,GETDATE())'
SET @END_DATE = getdate()

What I have tried:

I tried changing dates( entering it manually & using GETDATA() for various dates).It works for every date, in all format.
When I ask the data for Oct it returns data only for September 30th