> I tried the following mods to record what is inside post-command-hook.
> But this is too verbose and I wonder if there is a way to
> record the output of Fmessage() only to *Message* file
> instead of showing it to the minibuffer.
My previous suggestions were rather silly. The bug should occur with
`minibuffer-setup-hook', that is, within `minibuffer-with-setup-hook'.
You'd have to identify an object in your .emacs that causes
`minibuffer-setup-hook' to add a function to `post-command-hook' that's
triggering the bug, likely somewhere within `find-file-read-args'.
Could you try to edebug the latter?