Reusing Mautic contact ids

Issue
I created a new Mautic instance, added a few contacts using the UI. Then I started merging some of those contacts, just to see how it was registered and handled. Afterwards I connected an almost empty SalesForce DE org to start syncing some contacts (used for the contact_id field. After connecting and syncing those, I created and merged some more contacts using SF and the Mautic UI. When I started looking into what happened with the deleted (because they were merged) Mautic contact ids, I noticed that one was reused a couple of times.

I don’t think that this is the biggest issue, but I was wondering if this could interfere with the cookie and/or fingerprint tracking. I am also wondering if anyone else ever had this issue or if it could have been a hiccup on my system? (Which would be weird, since the MySQL table has auto_increment enabled on this column)

Background
A client wanted a plugin where we could de-duplicate users on a set of given contactfields. This would become a new plugin we would write, so I was doing some research on how the merging within Mautic works.

In the works: Allow plugin create own deduplicate logic by kuzmany · Pull Request #7502 · mautic/mautic · GitHub

Yeah, I know I found this thread as well. But unfortunately the client wanted it ASAP :frowning:

Also, this was only the reason my issue came to light, any idea why this is happening?