Ubus has been recently updated in 24.10. see it in the commit log of 24.10
https://git.openwrt.org/?p=openwrt/openwrt.git;a=shortlog;h=refs/heads/openwrt-24.10
Most packages get continuously recompiled, so the ABI versioned linkage in them should fix itself in a few days.
But some packages are marked target build specific, and will stay at rc4 compilation. So, some link errors will surface.
If you compile from scratch with full toolchain, you will get a coherent build.
(It is not really a bug, but an artefact of the two-stage build process in the buildbot.