The difference of working mode of eth-trunk causing network unreachable problem

Here is the information of S5700:
Management IP: vlan 4, 172.19.4.50
New vlan: vlan 184, 172.19.184.1
         vlan 185, 172.19.185.1

Information of S9712:
Management IP: vlan 4, 172.19.4.1

Two S5700 use stack function which act as one switch. Each switch uses one xgiga port to be eth-trunk port. The setting is as below:

interface XGigabitEthernet0/1/1
eth-trunk 15
interface XGigabitEthernet1/1/1
eth-trunk 15
interface Eth-Trunk15
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 4 184 185

S9712, which is configured by customer, has the same setting as S5700. After connect S5700 to S9712, I found that vlan 4 ip 172.19.4.1 in S9712 can’t ping 172.19.4.50 in S5700, as well as the vlan 184,185 ip. Through the troubleshooting, the eth-trunk 15 in S9712 has configured as below:

interface Eth-Trunk15
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 4 184 185
mode lacp-static