bug: Blank yellow screen on mobile Safari for some people

I haven't been able to repro because I don't have an iPhone but at least two people have reported it on mobile Safari. 

Knowns:
- Person A is not using iCloud Private Relay
- Person A said it "used to work"
- Person A said other mobile browsers also don't work
- Person A said it works on their iPad

Unknowns:
- Versions of iOS
- Versions of Safari