Directory 1002/ missing from /var/run/user/

From: Graham Perrin <grahamperrin_at_freebsd.org>
Date: Mon, 12 Jun 2023 00:32:42 UTC
What normally takes care of creation of the numbered directories?

A few hours ago, it was unexpectedly missing:

% whoami
grahamperrin
% ls -dhln ~
drwxr-xr-x  143 1002  1002   240B 11 Jun 13:38 /home/grahamperrin
% ls -hl /var/run/user
total 1
drwx------  2 root        wheel          2B 19 May 02:16 0
drwx------  7 bbsadmin-l  bbsadmin-l     7B  1 Jun 07:53 1001
%

Screenshot attached to yesterday's email; I was alerted to the absence 
by a run of Code - OSS.

I recreated the directory.