Blocked/Reblocked

Hello all,

Been searching for a difinitive answer on this.

I have someone whos blocked me, their profile pic is grey with the standard blocked 'user unknown'.

However, after a week, the profile picture reappears with their username, but unable to see posts and user followers etc.

Is this because that profile has unblocked and reblocked? Or does it revert back to that once you log out and back in via seperate accounts?