Glad you solved your own and shared back.
Couldn't see what was behind the error popup, but looked like you did the upgrade of code via git then used the GUI admin to complete the upgrade.
Why not, next time, finish the upgrade via command line?
After the git pull
php admin/cli/upgrade.php --non-interactive (that last part just hides the agreement screen)
That will show tables as they are upgraded/changed.
There is a long pause at end of that as Moodle now checks all settings.
Because caching is always present in a moodle now, one of my last lines in my up script is:
no options to that script and might also pause a farily long time.
First access/click in Moodle then will begin to rebuild those caches so site might be slow to render a memory intensive screen, but eventually site speeds up.
I also run cron.php while there ... it has task/routines for 'clean up'