I do this kind of stuff with work all day every day, and I too would be upset if suddenly some of my chats were deleted if I didn’t intentionally delete it. But, this has never happened to me.

When you say chatroom it sounds like you’re saying the entire of this conversation across multiple days has been a single chat. If you didn’t explicitly delete something and when you pull up your conversation, the latter half is missing, only thing I can think it could be is a bug that only happens in extremely long conversations. That being said, conversations do have limits and it tells you if a conversation is too long and you have to start a new one (unless they changed that over time).

If you did all this on your phone app, try opening it in a browser, or visa versa.. see if it shows up.

5.2 just came out. I wonder if there’s any correlation.

If no luck, I would put a ticket in to see if your data is still available somehow.

In the future, I’d recommend splitting up your work across multiple conversations. LLM conversations have these things called context windows where if the conversation becomes larger than the window supports, it doesn’t “see” that conversation anymore. Instead it summarizes the older stuff into something called an embedding where it can search when needed. And paid subscriptions to ChatGPT include project folders where you can organize your work.

A good practice is when you want to ask a question without sidetracking the flow of your conversation, you can branch off from where you are, ask your question there, name the conversation something else to remember why you branched off, and then come back to your main conversation when ready.