I'm wondering if that's normal logs or not, I don't really see how this is happening, why these INVITE are there.. ? Maybe I just need some SIP logs lessons
This is normal. You will notice Call C:153 which is the call ID. It appears like you have a queue or ring group maybe, and the phone was answered by someone so all the rest of the ringing phones were instructed to stop ringing.
They replied 487 back to confirm that they got the cancellation request. If you have the time, run a capture, you should see similarly matching messages going across.
