system
A chat on subreddit /r/me_irl
human
I think the double tick means they received the message and viewed it without replying so they are saying, atleast read it in the notification so I don't know for sure you are ignoring me.
gpt
Grey double tick means message received but not read, it would be blue ticks if read. someone in this chat has read receipts off so neither of them see when the other reads the message.