This delay still occurs in iOS 18.1 RC (22B82) on iPhone 16 Pro when Apple Intelligence is enabled. This is an unacceptable amount of delay for time sensitive notifications, for example - push notifications from the Duo MFA application do not appear until 10-12 seconds, and the time out to response is only 20-30 seconds. I filed my own feedback fro this under FB15418918, which reports "More than 10 similar reports". The only solution I've found is to completely disable Apple Intelligence.