That is hard to say without seeing the DOM and/or the properties of "lv-col-lg-2". Based on the flex property, a couple of things might be the case:
I would very much recommend reading trough this handy guide: https://css-tricks.com/snippets/css/a-guide-to-flexbox/
Just a heads up, you're working with a list view. This means you need travers down to the correct DOM-level in order to apply the styling (.mx-listview > ul).
You can also check out my mFlex module. This will give you those flex options in containers, listviews and templategrids. https://marketplace.mendix.com/link/component/205993
Good luck!
Maurits