<|endoftext|> - security issue?

I found that ChatGPT (currently ChatGPT May 24 Version) potentially has a bug when it’s responding with the endoftext token “<|endoftext|>” in a message.
It starts to respond with seemingly random texts, this might be a security issue, if this is a text from another context. In my case, it responded with health-related information each time, completely unrelated to our chat:

It also completely forgets any previous conversation immediately.

Faced the same thing after getting back to my previous request after few days