Something that isn't clear to me in the other discussions on this topic:
Low-rep users can't write comments on anything other than their own posts (questions or answers) or answers to their own questions. Nor can they participate in chat unless explicitly invited.
Evidently, the "automatically move this conversation to chat" mechanism has been fixed so that such users can participate in the chat created thereby.
But when a moderator manually moves a long discussion to chat, can the low-rep users whose comments were moved participate in that chat room? This happens fairly often on EE.SE.