Private link to tasks and calendars

I have a Murena account which I share with my wife. We have 3 calendars: for my own appointments, for her own appointments and for shared appointments. For tasks we have also three lists with the same functionality.
The private link (PL) to both my calendar and my tasks is the same: The PL for the other two calendars have at the end the name of the respective calendars, but for the corresponding tasks lists they have an added number “_1” and “_2” to the PL.

On our phones this works as expected.
For our desktops we use Thunderbird. Here the PL to both calendar and task list are the same and can not be changed in Thunderbird. Therefore calendar and tasks work as expected for me, but the tasks for her and the both of us are not shown in Thunderbird.

It seems that the same PL for calendars and tasks are no problem in Murena, as they are the same for me. It would be extremely nice if the PL for my wife’s tasks and those for us both would be the same as the calendar PL, but I can not change the tasks PL in the Murena account. Can this be solved?