Interaction between the *emacs* buffer and minibuffers?

[okomestudio]

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I'm debugging an issue in which the content of *emacs* buffer gets echoed to minibuffers in a condition which I have not been able to correctly identify.

The "echo" will produce many minibuffers (through *Minibuf-77*, in my live system), each minibuffer containing a portion of data in *emacs*. While these minibuffers are created, the control is on the current minibuffer just created; I cannot do anything in the main Emacs process (except the brief moment a minibuffer switches to a new minibuffer being created). All this seems to end in a parsing error at the end, without the receiver callback being executed.

I'm using async to perform a CPU-bound process in another Emacs process. When done, the process produces about 6.7 MB of data stored in a list of hashes. Then the main Emacs process receives the data in its callback.

This usually works fine. However, I've started noticing that in certain condition I started seeing the above minibuffer issue. I do use quite a few packages, so it's been a struggle to pin point what is causing this interaction. I can definitely make this happen deterministically in some condition, e.g., using a language server via lsp-mode in Python code.

I'd like to gather some clue as to how I could pin point how this behavior gets triggered. Could anyone offer some advice as to under which condition(s) could the content of *emacs* buffer starts getting echoed to the multiple minibuffers in the main Emacs process? I don't currently have a good intuition as to where to start looking, and I just want some tip to close in on a needle in a haystack.

Thank you for your attention.