XF 2.1 Server error when deleting users

[Stuart Wright]

I'm getting this error when I delete users (having found them in the admin panel and then hit Delete).
Nothing appears to happen with the modal, so I hit the Delete button again and then it processes.
The users are deleted.

• ErrorException: Fatal Error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 20971520 bytes)
• src/XF/Mvc/Entity/Manager.php:765
• Generated by: Stuart Wright
• Jul 20, 2020 at 3:58 PM

Stack trace​

#0 [internal function]: XF::handleFatalError()
#1 {main}

Request state​

array(4) {
["url"] => string(36) "/admin.php?users/antas.310423/delete"
["referrer"] => string(58) "https://www.avforums.com/admin.php?users/antas.310423/edit"
["_GET"] => array(1) {
["users/antas_310423/delete"] => string(0) ""
}
["_POST"] => array(7) {
["rename"] => string(1) "1"
["rename_to"] => string(21) "Deleted member 310423"
["_xfRedirect"] => string(58) "https://www.avforums.com/admin.php?users/antas.310423/edit"
["_xfToken"] => string(8) "********"
["_xfRequestUri"] => string(34) "/admin.php?users/antas.310423/edit"
["_xfWithData"] => string(1) "1"
["_xfResponseType"] => string(4) "json"
}
}

Any idea where to start fixing this please?

 

[Harpers Tate]

I did a couple this morning but importantly did NOT request a rename. And they both processed just fine first time. Whereas an earlier one WITH a rename did the same misbehaviour + server error. Hence - suggests the error is related to the renaming element.