Bugs in content types

I'm revising a set of Wordpress pages (using Safari on a Mac Mini), and when I revise Fill the Blanks and Single Choice activities, after I click update, a new line and an X are inserted after any changed item. Looking at the page source, the added text is: 

\\n\\n\\n \\n\\n \\n\\u00d7\\n\\n \\n\\n 

I am not typing this in - the multiplication sign is being added when I save and it only appears by the changed items. I have updated 'Fill the blanks' to the latest version. 

Apologies if this has already been posted. I did search the forums but couldn't find anything quite like this. WE use h5P to check if staff have watched the videos. Some staff are reporting they are unable to complete. After exhaustive testing, I have discovered a reliable way fo replicating the error. The only solution I can currently think of is t edit the text to ask the learner not to refresh but select continue.

Brothers : Firefox and Chromium

H5P : 1.20.2

LMS : Moodle 3.8.2+ (Build: 20200408)

Theme : Moove

I have already installed several H5P modules but I cannot install the column module.

The installation starts then the page refreshes but nothing appears and impossible to save, only the Cancel button is clickable.

Thank you,