I wouldn’t think the Wi-Fi network that you use would cause this.
It may just be a security thing??
As when you set up the eufy app it asks you for your region you’re located in and also set a time zone, so this could be some kind of deterrent to stop overseas hacking.
It’s a bug. The phone and camera are in different timezones. Some of the cameras get it correct and some don’t. I get misaligned times across my 10 cameras. Solution for Eufy is to store all times as UTC