Subscription on Report with Multi Value Parameter not working in Portal V2

When we activate the new Portal V2 design on the report server we have a problem with subscriptions on paginated reports. If the Report has a parameter that allows multiple values to be selected we can't specify a value for this parameter. We can open the dropdown and select different options in it, but the text box that displays the value of the parameter isn't updated and if we try to create the subscription, we get an error, that the parameter needs a value. If we turn off the new Portal design we can change the parameter as usual. Is this a bug in the new design? 

We have the Report Server Version1.10.7698.27886(January 2021) installed.