If there are no spaces it should be fine; can you save and open the product page again on an Incognito web to check whether the issue is gone?
This is an accepted solution.
I just noticed that you have images that are not being displayed/used in your description:
I think that actually this is the cause for the square. Delete them from your description and let me know whether it works.
You're welcome! Wishing you a nice week.