Hello, and welcome!
I saw your same post on the misc@ mailing list. You are more likely to get help there, as there are few active isakmpd(8) users on this small forum.
I don't. But your problem will be easier for people to review and help you to debug if you follow up your misc@ post with both a dmesg(8) and all of the applicable configuration files you are using with isakmpd, with any identifying information (such as keys and "real" IP addresses) redacted.
The isakmpd() program can be used with its own configuration and policy files, or can be used as a member of a tool chain with other applications such as bgpd(8) or ipsecctl(8). It is not clear from your misc@ post how it is being deployed.