Url parameters are not saved if poll units are on a landing page

I tested this. Url parameters are in the participants export for voters only if they are not on a landing page.

Landing Pages don’t support URL parameters. Because of this, they cannot pass the parameters on to the PollUnits linked within them. If you want URL parameters to show up in the participant export, the PollUnit needs to be accessed directly (without a Landing Page).

Please add this to your documentation.

Update: Pass URL parameters through landing pages

Landing pages now forward allowed URL parameters to their linked PollUnits.
You don’t need to configure anything on the landing page itself; each linked PollUnit has its own allow-list.
If the landing page detects allowed key-value pairs, those parameters will automatically be appended to the PollUnit link.