I have a page already set up with Suite widgets. Mainly Popup widgets for date and time pickers (Calendar / TimePicker) and I found that the popups stopped working properly as soon as I added the Vault CSS and JS files.
I eventually realized that, if I use the vault.css instead of vault.min.css everything started working properly. There appears to be something different in the minified version causing strange issues with the Popups from the Suite.
I’m using the Suite 6.2.1 and Vault 3.0.