3.6.12 phpList Updater update silently failing

it gets all the way through the four steps , all showing good. But never moves on to the final step where it updates the database! I’m upgrading from 3.6.10 ( whihc did auto-update OK)

Have tried twice with same results. here is our config:

PHP Built On Linux [redacted] 3.10.0-1160.83.1.el7.x86_64 #1 SMP Wed Jan 25 16:41:43 UTC 2023 x86_64
Database Type mysql
Database Version 5.7.41
Database Collation utf8mb4_general_ci
Database Connection Collation utf8mb4_general_ci
PHP Version 8.0.28
Web Server Apache
WebServer to PHP Interface apache2handler