I tried the following but no stack-trace is produced:

rm -rf .emacs .emacs.d
cat > /tmp/agenda.org << orgfile
* Anniversaries
:PROPERTIES:
#+CATEGORY: Ann
:END:
%%(org-bbdb-anniversaries-future 3)
orgfile

emacs

package-install bbdb
bbdb-create
Just some name
(i)nsert a field "anniversary" for that record
with content "1998-mm-dd something" and month/day of next day
(s)ave the bbdb file
find-file /tmp/agenda.org
org-agenda-file-to-front
customize-option calendar-debug-sexp toggle on
org-agenda

Message: Args out of range: 52, 55

Agenda looks like this:

Week-agenda (W42):
Monday 14 October 2024 W42
Ann: somethi -- tomorrowng

On Sat, 12 Oct 2024 at 12:45, Ihor Radchenko <yantar92@posteo.net> wrote:

Alexander Lazarević <laza@e11bits.com> writes:

> In one agenda (personal.org) I have the following entry:
>
> * Anniversaries
> :PROPERTIES:
> #+CATEGORY: Ann
> :END:
> %%(org-bbdb-anniversaries-future 3)
>
> This works for BBDB entries that have an anniversary like "1973-06-22"
> or "2021-04-91 wedding", but it fails for something like "1998-03-12 %s
> created bbdb-anniv.el %d years ago" (from the examples in ol-bbdb.el).
>
> The error message is:
>
> Bad sexp at line 5 in /home/laza/exobrain/org/personal/personal.org: (let
> ((entry ) (date '(10 8 2024))) (org-bbdb-anniversaries-future 3))

Please set `calendar-debug-sexp' to t and try to build agenda again.
Emacs will then produce an actual backtrace, detailing where the error
is.

--
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>