Thank you for reporting the issue to us.
We have fixed the issue in the latest version of InDesign, Id 14.0.3
Please upgrade your InDesign application to the latest version to try out the fix.
If you are unable to see the update yet, go to Creative Cloud desktop application, open the menu (three dots) from the top-right corner and click on ‘Check For App Updates’.
If you face any problems with the new update, do let us know in the comments.
You may also follow the below given link for the list of all fixed issues in Id 14.0.3
Margins not adjusting when a new master page is applied is a HUGE problem for those of use who are book designers. Our first page of a new chapter always has a larger top margin than the rest of the pages and when a book has 100+ chapters, manually changing each page is just very frustrating and a waste of time...especially when it USED to work perfectly. There is no work around other than to use an older version of InDesign, which is sad because the newer version DOES have some great features that I'd like to use. PLEASE fix this issue ASAP!Anonymous supported this idea ·