By using git filter-repo I have rewritten some history removing some data.
The repository size has been reduce but the old commits are still visible using direct links: they are no more accessible by using the text search in the "Commits" area.
On top of the screen is visible the following message: "This commit is not reachable from any branch or tag in this repository. It may be from a fork outside of this repository."
I surmise it is something similar to the following post: https://community.atlassian.com/forums/Bitbucket-questions/This-commit-is-not-reachable-from-any-branch-or-tag-in-this/qaq-p/2703261
Commit URL example: https://bitbucket.org/rfeisp/api-website/commits/8cff9efe7159751ec1adeef894432ae74043241a