Skip Collins <skip.collins@gmail.com> writes:

>> > ("n" "Note" entry
>> >       (file "~/Documents/org/beorg/capture.org")
>> >       "* %^{note} :note: %(org-set-property \"Created\"
>> > (org-time-stamp-inactive '(16)))" :immediate-finish t)
>> ...
>> This is quite a hacky capture template...
>
> I'll take that as a compliment.

It was not. Your template expansion only works by accident because of
internal details of implementation of org-capture-fill-template.

In particular, org-time-stamp-inactive not only returns a timestamp, but
also _inserts_ it at point (see the screenshot of interim buffer state
while expanding your template). The fact that this inserted timestamp
gets deleted is simply because (1) org-capture-fill template does not
expect the buffer to be changed by other functions; (2) org-capture-fill
internally marks %(sexp) with sticky text property and deletes
everything marked with that property at the end of expansion; (3)
org-time-stamp-inactive respects text property stickiness.