I've been watching this bug on other forums, even here... There's no scroll bar on published prototype, that's frustating trying to explain to my clientes how to access to the rest of the design, seriously, this is something very silly for you to fix it, please made my day!
You're right, there's no scrollbar in the prototype.
In many apps, applications, and web browsers, as well on desktops and mobile, scrollbars are not always present anymore. Sometimes they do appear while you're scrolling. But it's a bit of a vague feature in most environments and operating systems (and also a user preference), so try not to make a big deal out of it. Any user will have got used to their own device and settings, whether or not to try scrolling.
Nevertheless, it could be an option if you prefer it.
So what is the solution for the scroll bar not showing?
Can we be given the option to turn it on or off in the XD share links menu?
Some of our people at my company can not scroll down without a scroll bar.
I had clients as well that could not scroll without the bar.
Also the scrolling on the preview is very rough, doesn't scroll smoothly and sometimes not at all when I'm using my scroll wheel on the mouse.
Thank you for your time.
I am sorry for the frustration. It does look like you are looking for this feature: https://adobexd.uservoice.com/forums/353007-adobe-xd-feature-requests/suggestions/34467730-show-scro... If so, I would request you to please submit your feedback and upvote the request to add your voice.
This is the best way of communicating with our engineering team.
Hope it helps.