Hi @mso1,
welcome to the community (and the dev area).
There could be a few things that might cause this issue.
1. Version B is not including required JavaScript/CSS files.
This might have been caused while cloning it.
There are many ways how to include those files:
- If you’re working with the design-manager, the easiest way to include such files is via the right sidebar(below the style fields).
- Using the require_css, require_js and/or require_head functions. If those options should have been used in your slider module and you moved the cloned version to a different path you might want to check the paths to the files.
- directly in the module.js/module.css (those should have been cloned automatically)
- If you’re moving Version B from a theme to another theme. Quite often themes have their own bits and pieces all over the place which might not seem related to the module but are required in some way.
2. The code has an error
Since this is a slider and you’ve mentioned that the only difference between Version A and B is that Version B doesn’t have a video option, I’ll assume that the (original) slider has many options like image, video, maybe blog posts, content… Those options are - most likely set with some sort of an if-statement. A potential error might be that even if the video option was removed from the functions(right sidebar) and potentially from the code(module.html) it might cause an error in the if-statement which then causes an error in the slider functionality…
If other elements are affected, it might be a general setting. For instace if you have deactivated the jQuery option in the page settings recently. If you’re using an older theme it might not have a dedicated jQuery script and requires this option.
Note: Please don’t enable the jQuery option in the settings if you(or somebody from your team) hasn’t deactivated it recently - it might cause more problems than solve some 
Just to minimize other potential error sources:
- What theme are you using? (Default, Marketplace, custom, child-theme of default or marketplace)
- Where did you get the slider module from(theme, marketplace, custom development)
best,
Anton