After fighting with Lucas for a while, I returned to computer and reloading this page:
produced this output:
Notice: Trying to get property of non-object in /lib/adminlib.php on line 5198
Most probably incorrect set_page() url argument, it does not match the httpswwwroot!
line 837 of /lib/pagelib.php: call to debugging()
line 5200 of /lib/adminlib.php: call to moodle_page->set_url()
line 29 of /admin/report/unittest/index.php: call to admin_externalpage_setup()
And then one big red box with:
The fact is that the session had expired, so expected behavior should be to get redirected to login page or so. All the output above seems wrong IMO.
Not sure if this affects to all the admin pages or no, or if it can be fixed in one common way.