Open a Writer document. Insert → Pagebreak On second page: Form → Group Box Draw the box and a wizard will appear. First step: Create 2 option fields ("a", "b") Second step: → next Third step: → next Last step: → Finish Box will appear between first and second page. Group together with the radio buttons will has got height as the page height. Radio buttons could be seen at the top of the first page when content is moved to the right. Delete it and do the same on the first page. Have a look while you draw the box. It will be shown as anchored to paragraph. Have a look at the box when created. It will be anchored to page. Anchoring to the page is a good idea for View → Web (as it is used in Base), but in Writer with View → Normal you could only create a form on the first page. Position on another page is impossible. This bug appears in all LO-versions here. Oldest version I have installed is LO 5.1.5.2. So I think it is inherited by OOo. Detected under OpenSUSE 15.4 64bit rpm Linux.
The bug can be reproduced under Windows 11 with LO 7.5.2.