Making personalised urls using variables

We experimented making personalised xapi_launch urls with variables. It is working very well in the XOT xerte.graafschapcollege.nl/play.php?template_id=276
Next step was doing the same in a bootstrap xerte.graafschapcollege.nl/play.php?template_id=278
unfortunately this doesn't work, after filling in the name, everything changes well, exempt the url/link. the url as a text does change.
I attached the bootstrap in a zip-file

I cannot find any script in the LO you attached. Can you please indicate how this should work?

I use the variables table to determine the variables and links. On page one the students fills in their name and clicks on submit. Is everything works well, the students name is changed from "student" (standard fixed value) to the actual name.
The link with variables: xerte.graafschapcollege.nl/xapi_launch.php?template_id=213&group=2021&actor=[Naam]
The link shown as flat text: xerte.graafschapcollege.nl/xapi_launch.php?template_id=213&group=2021&actor=student
The link shown with filled in variable: xerte.graafschapcollege.nl/xapi_launch.php?template_id=213&group=2021&actor=Menno

There is no script, I only use the variables. In a XOT everything works well, in a Bootstrap not.