The GNU ELPA package vertico shows possible completion candidates in an
overlay during minibuffer completion.  I've just noticed that this
doesn't work properly when the generated eln file is loaded rather than
the el or elc file.

By "not working properly" I mean that frequently either the minibuffer
prompt is displayed or the overlay showing the candidates but not both.
Sometimes also both, but then the cursor is blinking at the end of the
candidates overlay rather than immediately behind the input.  Also the
candidate count overlay seems to be only shown if the prompt is also
there but not the canditates overlay.  Here's a screenshot: