If I remember correctly, cronned email are sent as admin.
But you're right, if admin has set "Not Receive His Emails" to Ys, emails may not be sent.

Ticket #4408 recorded.

I logged the session user from Cron.php with:
$tmp_uid=getSessionUser()->id;
debugTraceLog("SessionUserId: $tmp_uid");
$tmp_sid=session_id();
debugTraceLog("SessionId: $tmp_sid");

When I started the session with the admin user, I got:
2020-01-02 18:44:46.454 ----- DEBUG ----- SessionUserId: 1
2020-01-02 18:44:46.454 ----- DEBUG ----- SessionId: 7oh8hl08rs9csam21r1d73io9j

After I logged in with user no. 7, I got:
2020-01-02 18:55:10.430 ----- DEBUG ----- SessionUserId: 7
2020-01-02 18:55:10.430 ----- DEBUG ----- SessionId: jelaud20d00savspok904u1bqs

Regards,
Zsolt

It seems to me that when I log in in with a new user, then the cron session is restarted:
2020-01-02 19:06:53.543 ..... SCRIPT .... 172.29.25.180 =====/projeqtor/view/menuNotificationRead.php
2020-01-02 19:06:53.548 ..... SCRIPT .... 172.29.25.180 Page=menuNotificationRead.php
2020-01-02 19:06:53.548 ..... SCRIPT .... 172.29.25.180 refreshParameters()
2020-01-02 19:06:53.556 ..... SCRIPT .... 172.29.25.180 getProfile(objectOrIdProject=Audit #452)
2020-01-02 19:06:53.556 ..... SCRIPT .... 172.29.25.180 getProfile(objectOrIdProject=Audit #452)
2020-01-02 19:06:57.274 ----- DEBUG ----- Cron possibly running twice
2020-01-02 19:06:57.275 ----- DEBUG ----- current process ID is 879
2020-01-02 19:06:57.275 ----- DEBUG ----- current unique ID is 5e0e30cec37667.39453628
2020-01-02 19:06:57.275 ----- DEBUG ----- running process ID is 29931
2020-01-02 19:06:57.275 ----- DEBUG ----- running unique ID is 5e0e313d0a4ce1.50314662
2020-01-02 19:06:57.275 ----- DEBUG ----- => stopping current Cron
2020-01-02 19:06:57.825 ..... SCRIPT .... 172.29.25.180 Page=checkAlertToDisplay.php

I may find what the problem is:
https://www.projeqtor.org/en/forum/2-submit-issues/10465-running-of-cron-is-not-correctly-checked#26182