Why someone cannot see/chat after leaving the meeting?

Credmontgo Hello again, finally I have access to all work related stuff and here's the official info about the roadmap id Microsoft 365 Roadmap | Microsoft 365

A participants access to meeting chat will be dependent on how they were invited to the meeting:

• Who can see the chat for a single meeting?
  • People who are invited to the meeting or forwarded the meeting invitation after it is scheduled have access to the chat before, during, and after the meeting (up to the 1000-person limit).
  • People who are added to a meeting after it starts using the Invite someone field on the Participants pane (or are provided the meeting join coordinates in another way) will have access to the chat from the time they join to the time the meeting ends. They will not be able to see chat that takes place after the meeting ends.

• Who can see the meeting chat for a recurring meeting series?
  • People who are invited to the full series have access to the chat before, during, and after the meeting (up to the 1000-person limit).
  • People who are forwarded the invite of a single occurrence of the series or added to a meeting after it starts using the Invite someone field on the Participants pane (or are provided the meeting coordinates in another way) have access to the chat from the time they join to the time that meeting instance ends. They will not be able to see chat that takes place after the meeting ends.

Note: These changes do not impact channel meetings.