Also a Plus user. Same problem.
Like vffrench above, no logout is necessary to produce this behavior. After refreshing or switching conversations (or restarting browser), some or all of the most recent block of responses are gone. When I regenerate, some of them may reappear along with the newly generated response, or not.
For example, say I generated 4 responses for my most recent prompt in a given conversation. When that conversation is reloaded, that whole block of 4/4 responses is gone. When I regenerate, 2 of them might show back up when it generates a new 3rd response. Or none of them, and it just starts over on that block of responses.
I’ve tried clearing my openai cookies; didn’t help.