I'm facing similar issue under these conditions:
Running on iOS 15.2 (19C5044b)
App is running in foreground and is actively receiving touch inputs
Background App Refresh was disabled previously, and have been enabled in this OS version
I tried restarting the device minutes ago
The silent push was sent by CloudKit server due to a recent CloudKit data modification on another device
I can receive the push on another device on iOS 14.8, which has its Background App Refresh disabled for all apps
The log I got on iOS 15.2:
dasd
Subsystem: com.apple.duetactivityscheduler
Category: scoring
com.apple.pushLaunch.com.jonny.dictionary2:2E6024:[
{name: ApplicationPolicy, policyWeight: 50.000, response: {Decision: Absolutely Must Not Proceed, Score: 0.00, Rationale: [{[pushDisallowed]: Required:1.00, Observed:0.00},]}}
{name: ThunderingHerdPolicy, policyWeight: 1.000, response: {Decision: Must Not Proceed, Score: 0.00, Rationale: [{timeSinceThunderingHerdTriggerEvent < 300}]}}
], FinalDecision: Absolutely Must Not Proceed}