Update: Apple released iOS 11.2.5 beta 7 on January 19 which appears to be the golden master. The official release should come the week of January 21.
The latest iOS 11.2.1 update did not fix the Suica notification bug for me. I installed iOS 11.2.5 developer beta 1 and am happy to report that Suica notifications are working again in that beta. 11.2.5 will be mostly performance tweaks, Apple Pay Suica performance seems to be getting attention in this round.
As a rule I do not install beta software on my iPhone but the 11.2 Suica notification bug was irritating, iPhone X Suica performance ragged enough and the iOS 11.2.5 update number jump low enough to give it a go.
I do not suggest that others do the same. Let me deal with the messy Apple Pay Suica testing and keep you up to date on beta progress in this blog.