I think this is a bug, I have the same problem.
Even if I delete pages, the space used keeps increasing. When I try to rename a page to the name of a page that I deleted weeks ago, it says: page name already exists.
So i guess it keeps deleted elements somewhere invisibly in the background, and the space used doesn't decrease.
Also somehow related: the revisions function doesn't work anymore.
Would be great if someone could look into this.
And thank you for this lovely and brilliant tool! I'm so happy that hotglue is still working after more than 10 years.