I have a similar problem too. MacbookPro 10.14.6 (18G6042) and Safari 14.0.1. Automatic updates freeze the Mac, spinning wheel, and only way out, is forced shutdown. Happened with last 2 OwnCloud updates. Just installed OwnCloud 2.7.3 (build 2877) now, happened also with installing ownCloud-2.7.1 (build 2560).
Contacted their support and informed them, but OC showed little interest…: “OwnCloud ( we ) do not support users of our free software version - ownCloud Community Edition.”
… I don’t need support, its only assistance to their product development.
Maybe some of you have other channels to reach the programmers. Else I give up. It will affect many academic users here in NL of Surfdrive (an OwnCloud clone) when they reach this update.
To get a proper new installation avoid the auto-update, I did: download the desktop app from the OC website and install the package.