GitHub failing to load many pages

Many pages are failing to load in Safari (Actions runs, authenticated landing page, profile popup, etc). I’m seeing these messages in the browser console:

[Error] ReferenceError: Can't find variable: BroadcastChannel
	(anonymous function) (environment-47419ff1.js:1:5120)
	Global Code (environment-47419ff1.js:1:11966)
[Error] ReferenceError: Can't find variable: System
	Global Code (chunk-frameworks-4fe16dcb.js:1)
[Error] ReferenceError: Can't find variable: System
	Global Code (chunk-vendor-104567b3.js:1)
[Error] ReferenceError: Can't find variable: System
	Global Code (behaviors-24aa7714.js:1)
[Error] ReferenceError: Can't find variable: System
	Global Code (workflow-run-e89fd10a.js:1)
[Error] ReferenceError: Can't find variable: System
	Global Code (workflow-runs-47fd1130.js:1)

Sounds like someone assumed they could use BroadcastChannel, but it’s not supported on Safari: BroadcastChannel | Can I use... Support tables for HTML5, CSS3, etc

Hi there! Thank you for your post. Have you tried different browsers as well or is this just the case in Safari?