Thanks for your comment, but in fact, I have not been inserting that tag. I checked my files and my template, and that tag is not among those that I generally use for my posts. Somehow, it seems to be entered automatically.
On the Steemit post, I managed to edit it and remove that tag. However, I have not been able to do remove that tag from the SteemLeo post.
When I make my next post, I'll check to see if there's any way I can manage to prevent that tag from appearing.