PING -S can't work

[kite]

I found a strange problem, when ping the LAN address, It's still use the PPPOE public IP address as src address, even if I specify the source address user ping -S lan addr. When the LAN gateway is not opnsense, it cannot be pinged. when disconnect pppoe,then ping is ok.
opnsense lan addr is 192.168.100.123, PC is 192.168.100.66。PC ping opnsense is ok.

ping -S 192.168.100.123 192.168.100.66

the capture:

Frame 1: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)

Frame 1: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)
Ethernet II, Src: FreeBSDFound_10:f3:0f (58:9c:fc:10:f3:0f), Dst: HonHaiPrecis_8d:78:cc (1c:66:6d:8d:78:cc)
    Destination: HonHaiPrecis_8d:78:cc (1c:66:6d:8d:78:11)
    Source: FreeBSDFound_10:f3:0f (58:9c:fc:10:f3:0f)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: XX1.72.73.XXX, Dst: 192.168.100.66
Internet Control Message Protocol


my opnsense version is OPNsense 24.7.9_1-amd64
it's amazing...............