This happens usually when you input the text in a textarea widget for example and then use the same attribute to be displayed in a rich text editor.
There are two solutions:
1) Replace the textarea/textbox with a rich text, then it generates the HTML elements correctly.
2) When using the rich text editor on a page, then in the microflow from which the page is shown create a string variable with the contents replaceAll($Object/attribute, '
', </br>. NB! It is very important that the replaceAll second parameter is ' + create a line break using Enter + '.
Rich text editor and text area handle line breaks differently.