Hi @badaei really good question & one talked about earlier on this forum. In order to add a site to Cloudflare, you need to alter the nameservers at the registrar to establish ownership.
I checked what I can and don’t see activity that shows this movement (I could be looking at the wrong “droid”, however).
If you contact support, to login to Cloudflare and then contact Cloudflare Support. , they can look at the history. As the name servers did not change from what you’d set originally (theo), it does not seem like anyone else added your domain on Cloudflare nor were they able to alter your name servers with the registrar.
Edit - in your audit logs, do you show any edit to your DNS records that could account for a redirect? Like a change to your origin IP server?
Second edit - this is an old but great article about name servers.