Legato communication problem - SMACK eating SCM_RIGHTs data?

We’re cross-compiling the Legato framework for a custom ARM board (Toradex i.MX6D, kernel version 4.9) via a yocto sdk.
Everything compiles nicely but the components cannot communicate with one another. I’ve tracked the issue down to unixSocket.c unixSocket_ReceiveMsg, where the MSG_CTRUNC flag is set when a file descriptor is requested.

It seems to work shortly if I drop the security flags on the named pipes in /tmp/legato but this will introduce security holes.

Does anyone have a fix/workaround for this?