Only minor-league surprising, but when you add Instructions in Form Editor…
… those become the
title attributes (i.e. hover/hint text) of the form fields, but not of the corresponding form labels:
This is probably not a bug — it just is what it is — but can be sub-optimal especially if you restyle Checkboxes sets.
Grab the code from the JS pane here to fix it:
<label> gets the same
title as its companion