Screen time is turned on on my appleID but on on my dad's

I have screen time turned on but recently I saw on my Mac that I have a passcode and I don't know it (I have never entered a passcode on my Mac), so I tried many different passcodes but it doesn't work. I toggled off and toggled on again the option "share between devices" but when I restarted it, it transferred the passcode to my iPhone too so I have a passcode on my Mac AND iPhone. And the most interesting part is that my dad hasn't turned on Screen Time so he hasn't entered the passcode.

Please help.