SYMPTOM:
Attribute qualification prompts displayed in list style provide the options to "Qualify" or "Select" elements of an attribute. If "Qualify" is chosen along with the "In" operator with the attribute's ID form, and an attribute element with a comma(,) in it is selected, the comma(,) is changed to semicolons in Strategy Web. This alters the report sql and outcome of the overall results/data returned after execution.
STEPS TO REPRODUCE:
Follow these steps to reproduce:
1) Create a simple table and column in sql server database, where at least one of the element in the column contains a comma (,)
2) Create an attribute, and an attribute qualification prompt (choose all the default settings in the Prompt Generation Wizard) using this column.
3) In Strategy Web, create a new report with the attribute and attribute qualification prompt from step 2.
3) Run the report and when prompted, select the below options:
4. Notice the comma(,) in the attribute element changes to semicolon(;) and is treated as 2 separate elements instead of a single element in the text area as shown below:

5. Execute the report, prompt answer alters report sql and outcome of the results.
CAUSE:
This is a known issue in Strategy 10.x with the attribute qualification prompt interface, specific to when selecting an attribute element that has a comma(a) using the 'In' operator in Strategy Web.
WORKAROUND:
To workaround the issue, choose the 'Equals' operator instead of 'In' for a single attribute element answer.

ACTION:
Currently this issue is being reviewed by Strategy for a potential code fix on an upcoming Strategy release. Please contact Strategy Technical Support for an update on the issue.
This issue has been logged as Rally ID:DE102292 and KB441215