To be clear, I wouldn't expect a breaking change seven release candidates in. But to answer your question, my "blame" is appropriate, since Openwrt chooses the versions for libraries and packages. Arbitrarily upgrading a major library without testing it against the dependent software (at least for compilation) is something that shouldn't be permitted this late in the game. Would need to:
1: Revert wolfssl to the one used in rc6, backport the security patches if needed.
OR
2: Upgrade strongswan to 6.0.0, probably too much if we're trying to make a stable release.
OR
3: Backport the strongswan patch if openwrt wants to stick with an older strongswan but a newer wolfssl.
I am prepping a patch for #3 now for a merge request.
Dude, you are running a "bleeding edge" / developer version.
If you encounter bugs or other misbehavior, then fix it! And/or write a bug report, but don't flame on the forum because something in your setup is "broken".
A release candidate is not and never where intendent to be run in a production network excecpt you know what you are doing! An RC is to be used for testing AND reporting any issues so the next stable version can be... you know... be stable.