I have a script started from local.start that: mounts a users sshfs, logs the user in, and starts x. That all works fine. Now i tried installing gensplash (livecd theme) - The splash works fine, but now my script is not run, or actually being killed prematurely. While investigating the problem i substituted my login script for one that just counts to a log-file. The result was that the counting script was terminated after between 0.1 -0.3 sec. If i switch off the splash while booting (remove kernel parameters) then everything works fine again. Reproducible: Always Seems that others have experienced this bug: http://forums.gentoo.org/viewtopic.php?p=4564679#4564679
Good that you didn't post neither ebuild version, nor emerge --info, not any errors/dmesg output or whatever. We cannot guess, sorry.
FWIW, fbsplash doesn't control the initscripts in any way, it can only receive info about them and even that happens via baselayout.