Hi Yves,
Using the modern booking form, the form does not advance to page 2 after clicking on the next button on page 1. Instead it tells me my booking is complete and I receive a confirmation e-mail from the website, even tough page 2 holds required fields.
I tried this on two different servers and with one fresh install of Joomla to see if it was my setup, but I was able to reproduce this on the other sever with fresh Joomla install...
Sebastiaan