Reporting Services Parameter Do Not Refresh And Display Correct Value

I am creating an RS with four parameters -

Parameter 1 = Date Period ex. 20081102
Parameter 2 = Start Date ex. 11/02/2008
Parameter 3 = End Date ex. 12/02/2008
Parameter 4 = Description ex. Period 20081102

For Parameter 2 and 3 it will have available values in a Date Range
ex. for Period 20081102 it will have a date range
for Parameter 2 = from 10/02/2008 - 12/02/2008
for Parameter 3 it will have from 11/02/2008 - 12/02/2008


The process flow goes like this:

1. I'll select value from parameter 1
2. Automatically parameter 2,3 and 4 should display corresponding values.
3. It works well on first try
4. if i'll try selecting another value for Parameter 1,
5. As expected it should display again the corresponding values for the 3 parameters but Parameter 2 is retaining the value for the previous Parameter.

Why is it happening?
Does it have something to do with the date range?
How does the sequencing for RS happens?
This scenario happens when date ranges for each Date Period have common values.