Is anyone else seeing the error message <t> is undefined when using Emacs? Occasionally Emacs will respond to a keypress with that error in the echo area and Messages buffer. The key is otherwise discarded but pressing it again will result in the correct action.
I’ve been seeing this error since Emacs 25. I vaguely remember seeing somewhere that it was a known error and was already fixed (it was probably this Emacs Stack Exchange question). I was disappointed to see the error still occurring under Emacs 26, although it doesn’t seem to happen as often.
I’m getting ready to file a bug report and am trying to gather as much information as I can. If you have any information on this bug or even if you’ve seen it please leave a comment. If you’ve seen the error, please include the Emacs version and your OS.