Webcalendar crontab sendreminders

After upgrading my calendar to 1.0.4 through one-click install yesterday, I kept getting hourly crontab messages about missing files in the include directory. I traced this to the sequence in send_reminders.php:

$includedir = "./includes";

include "$includedir/config.php";
include "$includedir/php-dbi.php";
include "$includedir/functions.php";
include "$includedir/$user_inc";
include "$includedir/site_extras.php";

and found that config.php unsets $includedir.

Not knowing where else config.php is used, I reset $includedir in send_reminders.php thus:

$includedir = "./includes";

include "$includedir/config.php";

//config.php unsets includedir
$includedir = "./includes";

include "$includedir/php-dbi.php";
include "$includedir/functions.php";
include "$includedir/$user_inc";
include "$includedir/site_extras.php";

I haven't received a crontab message since then, so presumably it worked!

None of this happened prior to the update to 1.0.4, and I didn't see any reference to this problem elsewhere in a search of the Forum, so maybe it's something unique to me. If so, I don't understand why it should be, because it's clear that the send_reminders script calls $includedir/config.php, and that config.php unsets $includedir. A puzzle.