New line problem

It’s not really a “glitch,” but a matter of styling. Different themes will style their paragraphs differently, including how much spacing to put after their paragraphs. With Infinity, the CSS rule which defines the styling of paragraphs is this:

p {
  line-height: 22px;
  margin: 0 0 22px 0;
}

So there is 22px of spacing after each paragraph (the third value for margin determines how much space goes at the bottom). To change the value, you can install a CSS plugin like Custom CSS Manager, or use the Custom CSS option in JetPack if you have that installed. Then add a rule like this:

p {
   margin-bottom: 26px;
}

Set the value to whatever suits you. And don’t add multiple line feeds (paragraph breaks) to change the spacing, that’s not the way web elements should be positioned.