It is being removed, but it's being removed too late for it to avoid the ACB conflict
Fatal error: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31) in /etc/inc/acb.inc on line 63
PHP ERROR: Type: 64, File: /etc/inc/acb.inc, Line: 63, Message: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31)pkg-static: DEINSTALL script failed
Saving updated package information...
Fatal error: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31) in /etc/inc/acb.inc on line 63
PHP ERROR: Type: 64, File: /etc/inc/acb.inc, Line: 63, Message: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31)pkg-static: POST-INSTALL script failed
[6/6] Upgrading pfSense-pkg-System_Patches from 1.1.8 to 1.1.10...
[6/6] Extracting pfSense-pkg-System_Patches-1.1.10: ......... done
Removing System_Patches components...
Menu items... done.
Fatal error: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31) in /etc/inc/acb.inc on line 63
PHP ERROR: Type: 64, File: /etc/inc/acb.inc, Line: 63, Message: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31)pkg-static: DEINSTALL script failed
Saving updated package information...
Fatal error: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31) in /etc/inc/acb.inc on line 63
PHP ERROR: Type: 64, File: /etc/inc/acb.inc, Line: 63, Message: Cannot redeclare acb_enabled() (previously declared in /usr/local/pkg/autoconfigbackup.inc:31)pkg-static: POST-INSTALL script failed
>>> Scheduling package pfSense-pkg-AutoConfigBackup for removal...
>>> Scheduling package pfSense-pkg-aws-wizard for removal...
>>> Removing unnecessary packages... done.
>>> Cleanup pkg cache... done.
pfSense 2.4.4-DEVELOPMENT amd64 Mon Aug 06 15:04:03 EDT 2018
Bootup complete
At which point it landed me at an Amnesiac login. I logged in and checked, but ACB was removed by that point. I had to issue a manual reboot and then it was OK.