So this isn’t a huge deal as the root group has root as its only user, but on my system, /sbin/splash_early is the only executable in /sbin that is group-writable:
osmc@osmc-rpi2:~$ ls -al /sbin/splash_early
-rwxrwxr-x 1 root root 991 Sep 2 08:13 /sbin/splash_early
Secure configuration guidelines for linux systems generally recommend that files in /*bin directories not be group-writable or world-writable, so that programs cannot be co-opted by malicious changing of those files.
Presumably this is just a quick fix in osmc/build.sh at 82faf42c528de5785c31580be3b32f8dab1750fd · osmc/osmc · GitHub
Version info:
osmc@osmc-rpi2:~$ grep VERSION_ID /etc/os-release
VERSION_ID="2016.09-1"
osmc@osmc-rpi2:~$ grep Kodi .kodi/temp/kodi.log | head -3
22:46:07 15.507114 T:1956348848 NOTICE: Starting Kodi (16.1). Platform: Linux ARM (Thumb) 32-bit
22:46:07 15.507246 T:1956348848 NOTICE: Using Release Kodi x32 build (version for Raspberry Pi)
22:46:07 15.507389 T:1956348848 NOTICE: Kodi compiled Aug 28 2016 by GCC 4.9.2 for Linux ARM (Thumb) 32-bit version 3.16.7 (200711)
Sorry if I should have just opened a github issue, but the guidelines said to make a forum post first.