Clear random squares appearing in un-formatted Body Text

Hi Not sure if this is a bug or not but I have been trying all day to fix this but its not making much sense:

1. Detailed steps to reproduce the bug (exactly how and when did it happen): Using the H5P Timeline template. When I pasted the text into the dates and eras body text, these random squares appear (see attachment). It is not at the end of a sentence or line as I first thought, and even if I completely strip the formating to bare text it still happens and I cannot get rid of it. It only happens in the Date and Era Body Text not on the first page of the timeline.  I have been searching online for possible solutions. Most of them tell me to remove the formating but I did this and it doesn't seem to work. I have even typed in clean text into the body text area and it still happens but it is not to do with going to the next line because it does not happen every time I go to the next line. So confusing and disappointing as I have spent hours building this timeline only to discover I cannot get rid of these unexplained boxes.
2. Platform and version number. E.g. Drupal, Wordpress, Moodle: Moodle version 3.11
3. Mobile or Desktop: Desktop 
4. Browser: Chrome, Firefox, Safari etc: Google Chrome, most recent version.
5. H5P plugin version: H5P framework v1.24 (h5plib_v124)
6. H5P content type and version (if a content type was used), and a sample URL or attached H5P.: HP5 Hub Timeline (downloaded from H5P Hub)
7. Any browser console errors: None
8. Any PHP errors: None
9. Screenshots if it's a visual problem: Yes attached.
10. Any recent changes to the environment (new plugins/modules, updates, configuration changes etc.) None
11. Any recent changes to the browser you're using (new extensions, updates etc.) None