If your page size is in multiples, (i.e. 748+748+748) 2244 pixels, when scrolling down the page, the page will snap to the next page. If you have created a document not in multiples and you have selected 'Paged vertical scrolling' option selected on your build form, it will snap again.
The option on the build form makes ALL pages scroll in chunks. Removing that option will allow both smooth scrolling and 'paged' scrolling depending on how you design your pages. So to solve your problem, please create a new build without that option to solve your problem to allow you to do both forms of scrolling.
Please follow the link below for more details on how to create vertical scroll-able page: