React Router broken on Safari 14

I just upgraded to OS X Catalina 10.15.7 which installs a new version of Safari v14.0. After the upgrade my React apps were broken in Safari, but fine in Chrome. When clicking on a menu item I get the message “This webpage was reloaded because a problem occured”, so I am unable to navigate in the app at all. I get the same behaviour with a clean sidemenu starter app, and I’m using Ionic 6.11.9.


Seems to be an issue with web-components and the Safari 14.0.0 Update (as liamdebeasi explained in the comments). There is also a workaround explained. Otherwise you/we have to wait for the next Safari Update.

Issue 21939

Okay, thanks for the explanation.