Hi jay
I gone through similar issue in plant maintenance webi report.
As mentioned by Neil; it is due to multiple values for each dimension.
Like my problem was there were 2 values for each maintenance type. 1. Planned vale; 2. Actual value
there are 2 work arounds for this issue.
1: if you wish to display all values; have sub columns for each of 1,2,3,4 ( i had 2 sub columns Plan and actual for each period. you will be required to use WHERE function in formula editor for each sub column)
2. very similar to above; if you need only 1 value, Like Actual only, use WHERE FUNCTION to fill column.
Regards
Rashid