Checkbox group with no checked value defaults to its default value (instead of b

[VincentD]

Hi, community!

We're looking at using a checkbox group for a Yes/No selection, but only with one choice, Yes, so it can be checked or unchecked. The checkbox is configured with only one static choice, being Yes, and with a default selection being yes as well.
Things are working fine when using this in a simple report, Yes being returned when the checkbox Yes value is selected, blank/null when it is not.
When drilling through though, when the checkbox is deselected, the checkbox is showing as Yes in the target report.
I understand the target report may interpret the null/blank value it gets as if the checkbox was not filled, thus filling it with its default Yes value. I have not found a workaround to this.
Notes:
- When Yes is selected, that's what the target report shows as well
- We do not want the default value of the checkbox to be something else than Yes
- We do not want to use a radio button, although the behavior is 'correct' in that case
- Trying to use another item to store the checkbox value does not work as it makes the field mandatory

Repro steps (5minutes):
Attached is a simple sample report that we want to drill through itself
Open the attached and copy all content
Create a blank report in Report Studio and choose Tools / Open Report from Clipboard
Paste
Change the report package to yours
Save
Go to Page1
Click on Drill Through
In Data / Drill-Through Definitions, double click on (Collection)
In Report:, browse to the report you just saved
In Parameters, click on the Edit icon
In both lines, select 'Pass parameter value' in the Method column and the parameter name (same as in column 1) in the Value column
Click OK then OK
Save
Run the report
Unselect the Yes checkbox and select No for the radio button
Click Finish
See there is no value for the checkbox and the radio button shows No. Fine
Click Drill Through
See the radio button value is still No (correct) while the checkbox shows Yes (unexpected)

How can we end-up with the checkbox value being blank/null in the target report when it is unchecked in the source one?

Note: I've reproduced this behaviour in Cognos 10.2.2 FP3 and FP7. It could be by design but I'd like a workaround.

Thanks!