I'm having display (CSS) issues with your form on admin page for category taxonomy.
I narrowed it down to poor css in the plugin itself:
The element with class rwmb-tab-panel has an inline style for display: block;
And I can see that it had display: table; which is now commented out as seen on the screenshot below: Inspect element screenshot
The problem is that you are putting children divs which have display: table-row; in that display: block; parent and, because they don't have an actual parent with display: table;, their width isn't rendered properly and no CSS for width will apply to them (such as 100%, 75%, 100vw). Children divs inspect element