The public beta should be dropping soon and I’m traveling the next few weeks without connections so this public announcement is going out now: if you have an iPhone X Suica Problem unit do not install the iOS 12 public beta. Leave beta testing to developers and fools.
The current iOS 12 developer beta 2 is wreaking havoc on iPhone X Suica problem units with users reporting much higher error rates everywhere, transit gates, cash registers, vending machines, you name it. Stick with the iOS 11.4 devil you know: at least you have a 50% chance of getting through the transit gate without an error. Wait until the official release and then some. You’ll be happy you did.
UPDATE
iPhone X has a NFC hardware problem, for more information see:
iPhone X Suica Problem Q&A Exchange Guide (English Version)
iPhone X Suica問題Q&A交換ガイド（日本語版）