There are occasional issues that require workarounds with Gutenberg Blocks. When adding blocks, hitting return gives you the next block. Shift + return allows you to have two lines within the same block.
Working with columns for responsive sites can get tricky if your content doesn’t take up the same space. You can use the same shift + return trick to add some empty space to the top or bottom of a block without adding a space block. Also, sometimes columns on mobile devices look a little squished together. Add a little space block to the bottom of all but your last column will add a little elbow room without altering the desktop display.