cannot capture secure packets

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Hi there all, I'm a newbie, I have a question and I googled a lot but no luck. I have a Windows hyper-v lab environment with:

1. Server 2016 (ip 10.0.0.250) with IPsec VPN service installed;
2. Windows 10 (ip 10.0.0.180) which can IPsec VPN connects to server (10.0.0.250) and can also captures ESP packets.
3. Windows 10 (ip 10.0.0.181) which can captures all packets between 10.0.0.250 and 10.0.0.180 except ESPs.

Why Windows 10 (ip 10.0.0.181) cannot captures ESP? What mistake I made, Please advise!