SSRS 2008 - Report behave differently env to env

We develop report on SSRS 2008 R2 and deploy on SSRS 2008 server . Server report version are same for DEV,UAT and PROD env. While displaying Datepicker we set default to current date , this user can change , if user change to some other date from the parameter, on UAT click on chart drill down parameter been refreshed and set value to default, they lost user entered value . But while running on DEV,on click on chart drill down as said parameter refreshed but still retain same vale which user has been entered. Code are same ,server and rdl are same in both env. Please help to identify this issue.