upload package failed - "Code attempted dynamically-named method call"

I've just tried to update a package on Sugar 12.2 and hit this error on upload:

custom/src/cloudtech/ctsync/handler/connection/ConnectionAbstract.php
Code attempted dynamically-named method call on line 141
Code attempted dynamically-named method call on line 162
Code attempted dynamically-named method call on line 183
Code attempted dynamically-named method call on line 217

I tested uploading on sugarondemand versions 12.0.1 and 12.1.0 and they also exhibit this behaviour.
A local version of 12.0.1 does not complain about the dynamic methods.

I was unaware that this was functionality going to be black-listed, and I'm pretty sure that it was working on 12.x until recently.

There doesn't seem to be any mention in sugarclub.sugarcrm.com/.../sugar-12-0-q2-2022-customization-guide or the 12.1 and 12.2 guides.

Was it a security patch?