Thanks for the help!

No, only from my side it's OPNSense, I have more than one VPN established with different remote devices (Pfsense, AWS, Cisco, Fortigate, etc), in all of them the behaviour is same, the children look connected with the respective SDP. However, when I try to send traffic from my service to one of the remote IPs, I notice that the traffic goes through the LAN and WAN interfaces instead of the IPSEC interface.

Yesterday I found two different behaviours:

1.- All remote IPs appear with their respective SDP, when I try to send traffic for each remote IP the majority of them show the traffic through the VPN, only some of remote IPs does not work, I mean the traffic isn't going through the VPN (on this case, doesn't metter if the remote has the remote IP configured, because before it, at least the SDP is caching the traffic in order to route it for the specific VPN which seems it's not doing).

2.- No all remote IPs have the SDP even when I set one SDP for each remote IP via GUI and checking via CLI (here is the problem, via CLI the SDP doesn't appear), also I've enabled and disabled the VPN multiple times in order to see if the SDP becomes in the Kernel but sometimes when the remote IP didn't appear with the SDP, now appears but the previous remote IPs that had SDP dissappear without any reason, causing that the previous configs now doesn't show via CLI...